@article{21980, abstract = {Despite significant progress in the field of molecular electronics over the last two decades, the quantitative prediction of metal-molecule-metal junction conductance remains a challenge. The standard computational framework combines density functional theory (DFT) with nonequilibrium Green’s functions (NEGF) using low-rung exchange-correlation functionals such as PBE, which overestimate the conductances. More advanced correction methods exist but require complex workflows and high computational cost, limiting their accessibility. Here, we introduce a physically motivated approach that approximates results obtained with high-rung functionals. Our method fits the PBE-calculated transmission to a Breit-Wigner form and subsequently refines the fit parameters using molecular orbital energies and metal densities of states computed for the isolated subsystems with high-rung functionals. This approach is applicable to a broad range of molecular junctions yielding conductance values in quantitative agreement with experiments. Our approach is simple, low-cost, and accurate, making it well-suited for routine and large-scale prediction of single-molecule junction conductance.}, author = {Gulyaev, Artem and Hazarika, Jyotisman and Liu, Zhen-Fei and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {22}, pages = {7429–7434}, publisher = {American Chemical Society}, title = {{A computationally efficient and accurate method for predicting conductance of single-molecule junctions}}, doi = {10.1021/acs.nanolett.6c01462}, volume = {26}, year = {2026}, } @article{21521, abstract = {Fast-emitting scintillators are essential for advanced diagnostic techniques, yet many suffer from low radiation attenuation. This trade-off is particularly pronounced in polymer scintillators, which, despite their fast emission, exhibit low density and low atomic numbers, limiting the radiation attenuation factor, resulting in low detection efficiency. Here, we overcome this limitation by creating a heterostructure scintillator of alternating nanometric layers, combining fast light-emitting polymer scintillator layers and transparent stopping layers with a high radiation attenuation factor. The nanolayer thicknesses are tuned to optimize the penetration depth of recoil electrons in active emissive layers, maximizing the conversion of X-rays to visible light. This design increases light output by up to 1.5 times and enhances imaging resolution by a factor of 2 compared to homogeneous polymer scintillators due to the ability to use thinner samples. These results demonstrate the potential of heterostructure scintillators as next-generation detector materials, overcoming the limitations of homogeneous scintillators.}, author = {Be’er, Orr and Shultzman, Avner and Strassberg, Rotem and Dosovitskiy, Georgy and Veber, Noam and Schuetz, Roman and Roques-Carmes, Charles and Kaminer, Ido and Bekenstein, Yehonadav}, issn = {1530-6992}, journal = {Nano Letters}, keywords = {Scintillator, Heterostructure, Thin film, X-ray imaging, X-ray detector}, number = {9}, pages = {3422--3429}, publisher = {American Chemical Society}, title = {{Heterostructure nanoscintillator for matching radiation absorbing layers with fast light-emitting layers}}, doi = {10.1021/acs.nanolett.4c05353}, volume = {25}, year = {2025}, } @article{20221, abstract = {We describe the design, synthesis, and single-molecule junction conductance of π-electron molecules bearing both radial and linear π-conjugation pathways, whereby cycloparaphenylene (CPP) radial cores are π-extended linearly with aryl alkyne substituents as models for previously reported CPP-arylene ethynylene conjugated polymers. Although radially and linearly conjugated molecules have been studied previously in isolation as junction-bridging molecular electronic units, this is the first study to examine molecules where both topologies are operative. Our results reveal that the presence of radial CPP components within the junction-spanning pathway leads to a reduction in the conductance of the backbone compared to model linear phenyl substituents. Through tight-binding and DFT-based calculations, we attribute this conductance change to intramolecular van der Waals (vdW) interactions between the CPP ring and the junction-spanning arylene-ethynylene molecular backbone. These interactions induce changes in the dihedral angles of the backbone, leading to a reduced overlap of π orbitals within the molecular junction.}, author = {Shi, Wanzhuo and Wang, Mengjiao and Venkataraman, Latha and Tovar, John D.}, issn = {1530-6992}, journal = {Nano Letters}, number = {31}, pages = {12101--12106}, publisher = {American Chemical Society}, title = {{Single-molecule conductance through hybrid radially and linearly π-conjugated macromolecules reveals an unusual intramolecular π-interaction}}, doi = {10.1021/acs.nanolett.5c03693}, volume = {25}, year = {2025}, } @article{20528, abstract = {We study single-molecule junction formation of group VIII metallocenes─ferrocene, ruthenocene, and osmocene─with gold (Au) electrodes using the scanning tunneling microscope-based break junction technique. Unlike ferrocene, both ruthenocene and osmocene can form molecular junctions under ambient conditions without chemical linkers. We propose that Au electrodes bind to the metal center and one of the cyclopentadienyl (Cp) rings via a ring-slippage process, forming a molecular junction. Control measurements demonstrate that the metal centers bind to uncoordinated Au exclusively in the +3 oxidation state. Ab initio quantum transport calculations corroborate this mechanism for metallocene junction formation. This work highlights the formation of metal–metal (Ru–Au and Os–Au) bonds in metallocene-based single-molecule devices, challenging the assumption that metallocenes bind exclusively through van der Waals interactions between the Cp ring and the Au electrode. Our findings introduce a method for creating organometallic single-molecule devices with metal–metal bonds, enabling more stable and versatile molecular electronics.}, author = {Lee, Woojung and Prindle, Claudia R. and Shi, Wanzhuo and Louie, Shayan and Steigerwald, Michael L. and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {8}, pages = {3316--3322}, publisher = {American Chemical Society}, title = {{Formation of metallocene single-molecule junctions via metal–metal bonds}}, doi = {10.1021/acs.nanolett.4c06450}, volume = {25}, year = {2025}, } @article{20331, abstract = {Here, we present a foundational investigation of charge transport through three BODIPY-based molecules using the scanning tunneling microscope–break junction (STM-BJ) technique. We demonstrate that molecular conductance through the BODIPY core can be measured by introducing aurophilic linkers at the 2,6-positions. By varying these linkers, we systematically modulate the frontier molecular orbital energies and fine-tune transport behavior. Our experimental results are supported by DFT-based calculations, which feature a new computationally efficient correction to standard PBE-level transmission predictions. Together, these findings establish the viability of BODIPY-based systems for molecular junction applications and lay the groundwork for future studies of their single-molecule optoelectronic properties.}, author = {York, Emma and Stone, Ilana and Shi, Wanzhuo and Roy, Xavier and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {36}, pages = {13697--13702}, publisher = {American Chemical Society}, title = {{Tuning conductance in BODIPY-based single-molecule junctions}}, doi = {10.1021/acs.nanolett.5c03764}, volume = {25}, year = {2025}, } @article{19026, abstract = {The back-action damping of mechanical motion by electromagnetic radiation is typically overwhelmed by internal loss channels unless demanding experimental ingredients such as superconducting resonators, high-quality optical cavities, or large magnetic fields are employed. Here we demonstrate the first room temperature, cavity-free, all-electric device where back-action damping exceeds internal loss, enabled by a mechanically compliant parallel-plate capacitor with a nanoscale plate separation and an aspect ratio exceeding 1,000. The device has 4 orders of magnitude lower insertion loss than a comparable commercial quartz crystal and achieves a position imprecision rivaling optical interferometers. With the help of a back-action isolation scheme, we observe radiative cooling of mechanical motion by a remote cryogenic load. This work provides a technologically accessible route to high-precision sensing, transduction, and signal processing.}, author = {Puglia, Denise and Odessey, Rachel H and Burns, Peter and Luhmann, Niklas and Schmid, Silvan and Higginbotham, Andrew P}, issn = {1530-6992}, journal = {Nano Letters}, number = {7}, pages = {2749--2755}, publisher = {American Chemical Society}, title = {{Room temperature, cavity-free capacitive strong coupling to mechanical motion}}, doi = {10.1021/acs.nanolett.4c05796}, volume = {25}, year = {2025}, } @article{17857, abstract = {Gold–dithiol molecular junctions have been studied both experimentally and theoretically. However, the nature of the gold–thiolate bond as it relates to the solvent has seldom been investigated. It is known that solvents can impact the electronic structure of single-molecule junctions, but the correlation between the solvent and dithiol-linked single-molecule junction conductance is not well understood. We study molecular junctions formed with thiol-terminated phenylenes from both 1-chloronaphthalene and 1-bromonaphthalene solutions. We find that the most probable conductance and the distribution of conductances are both affected by the solvent. First-principles calculations show that junction conductance depends on the binding configurations (adatom, atop, and bridge) of the thiolate on the Au surface, as has been shown previously. More importantly, we find that brominated solvents can restrict the binding of thiols to specific Au sites. This mechanism offers new insight into the effects of the solvent environment on covalent bonding in molecular junctions.}, author = {Dalmieda, Johnson and Shi, Wanzhuo and Li, Liang and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {2}, pages = {703--707}, publisher = {American Chemical Society}, title = {{Solvent-mediated modulation of the Au–S bond in dithiol molecular junctions}}, doi = {10.1021/acs.nanolett.3c04058}, volume = {24}, year = {2024}, } @article{17859, abstract = {The electrostatic environment around nanoscale molecular junctions modulates charge transport; solvents alter this environment. Methods to directly probe solvent effects require correlating measurements of the local electrostatic environment with charge transport across the metal–molecule–metal junction. Here, we measure the conductance and current–voltage characteristics of molecular wires using a scanning tunneling microscope–break junction (STM-BJ) setup in two commonly used solvents. Our results show that the solvent environment induces shifts in molecular conductance, which we quantify, but more importantly we find that the solvent also impacts the magnitude of current rectification in molecular junctions. By incorporating electrochemical impedance spectroscopy into the STM-BJ setup, we measure the capacitance of the dipole layer formed at the metal–solvent interface and show that rectification can be correlated with solvent capacitance. These results provide a method of quantifying the impact of the solvent environment and a path toward improved environmental control of molecular devices.}, author = {Shi, Wanzhuo and Greenwald, Julia E. and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {30}, pages = {9283--9288}, publisher = {American Chemical Society}, title = {{Impact of solvent electrostatic environment on molecular junctions probed via electrochemical impedance spectroscopy}}, doi = {10.1021/acs.nanolett.4c02103}, volume = {24}, year = {2024}, } @article{13094, abstract = {Endocytosis is a key cellular process involved in the uptake of nutrients, pathogens, or the therapy of diseases. Most studies have focused on spherical objects, whereas biologically relevant shapes can be highly anisotropic. In this letter, we use an experimental model system based on Giant Unilamellar Vesicles (GUVs) and dumbbell-shaped colloidal particles to mimic and investigate the first stage of the passive endocytic process: engulfment of an anisotropic object by the membrane. Our model has specific ligand–receptor interactions realized by mobile receptors on the vesicles and immobile ligands on the particles. Through a series of experiments, theory, and molecular dynamics simulations, we quantify the wrapping process of anisotropic dumbbells by GUVs and identify distinct stages of the wrapping pathway. We find that the strong curvature variation in the neck of the dumbbell as well as membrane tension are crucial in determining both the speed of wrapping and the final states.}, author = {Azadbakht, Ali and Meadowcroft, Billie and Varkevisser, Thijs and Šarić, Anđela and Kraft, Daniela J.}, issn = {1530-6992}, journal = {Nano Letters}, number = {10}, pages = {4267–4273}, publisher = {American Chemical Society}, title = {{Wrapping pathways of anisotropic dumbbell particles by Giant Unilamellar Vesicles}}, doi = {10.1021/acs.nanolett.3c00375}, volume = {23}, year = {2023}, } @article{17865, abstract = {Understanding how molecular geometry affects the electronic properties of single-molecule junctions experimentally has been challenging. Typically, metal–molecule–metal junctions are measured using a break-junction method where electrode separation is mechanically evolving during measurement. Here, to probe the impact of the junction geometry on conductance, we apply a sinusoidal modulation to the molecular junction electrode position. Simultaneously, we probe the nonlinearity of the current–voltage characteristics of each junction through a modulation in the applied bias at a different frequency. In turn, we show that junctions formed with molecules that have different molecule–electrode interfaces exhibit statistically distinguishable Fourier-transformed conductances. In particular, we find a marked bias dependence for the modulation of junctions where transmission is mediated thorough the van der Waals (vdW) interaction. We attribute our findings to voltage-modulated vdW interactions at the single-molecule level.}, author = {Wei, Yujing and Li, Liang and Greenwald, Julia E. and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {2}, pages = {567--572}, publisher = {American Chemical Society}, title = {{Voltage-modulated van der waals interaction in single-molecule junctions}}, doi = {10.1021/acs.nanolett.2c04098}, volume = {23}, year = {2023}, } @article{11379, abstract = {Bernal-stacked multilayer graphene is a versatile platform to explore quantum transport phenomena and interaction physics due to its exceptional tunability via electrostatic gating. For instance, upon applying a perpendicular electric field, its band structure exhibits several off-center Dirac points (so-called Dirac gullies) in each valley. Here, the formation of Dirac gullies and the interaction-induced breakdown of gully coherence is explored via magnetotransport measurements in high-quality Bernal-stacked (ABA) trilayer graphene. At zero magnetic field, multiple Lifshitz transitions indicating the formation of Dirac gullies are identified. In the quantum Hall regime, the emergence of Dirac gullies is evident as an increase in Landau level degeneracy. When tuning both electric and magnetic fields, electron–electron interactions can be controllably enhanced until, beyond critical electric and magnetic fields, the gully degeneracy is eventually lifted. The arising correlated ground state is consistent with a previously predicted nematic phase that spontaneously breaks the rotational gully symmetry.}, author = {Winterer, Felix and Seiler, Anna M. and Ghazaryan, Areg and Geisenhof, Fabian R. and Watanabe, Kenji and Taniguchi, Takashi and Serbyn, Maksym and Weitz, R. Thomas}, issn = {1530-6992}, journal = {Nano Letters}, number = {8}, pages = {3317--3322}, publisher = {American Chemical Society}, title = {{Spontaneous gully-polarized quantum hall states in ABA trilayer graphene}}, doi = {10.1021/acs.nanolett.2c00435}, volume = {22}, year = {2022}, } @article{17872, abstract = {Coherent tunneling electron transport through molecular wires has been theoretically established as a temperature-independent process. Although several experimental studies have shown counter examples, robust models to describe this temperature dependence have not been thoroughly developed. Here, we demonstrate that dynamic molecular structures lead to temperature-dependent conductance within coherent tunneling regime. Using a custom-built variable-temperature scanning tunneling microscopy break-junction instrument, we find that oligo[n]phenylenes exhibit clear temperature-dependent conductance. Our calculations reveal that thermally activated dihedral rotations allow these molecular wires to have a higher probability of being in a planar conformation. As the tunneling occurs primarily through π-orbitals, enhanced coplanarization substantially increases the time-averaged tunneling probability. These calculations are consistent with the observation that more rotational pivot points in longer molecular wires leads to larger temperature-dependence on conductance. These findings reveal that molecular conductance within coherent and off-resonant electron transport regimes can be controlled by manipulating dynamic molecular structure.}, author = {Lee, Woojung and Louie, Shayan and Evans, Austin M. and Orchanian, Nicholas M. and Stone, Ilana B. and Zhang, Boyuan and Wei, Yujing and Roy, Xavier and Nuckolls, Colin and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {12}, pages = {4919--4924}, publisher = {American Chemical Society}, title = {{Increased molecular conductance in Oligo[n]phenylene wires by thermally enhanced dihedral planarization}}, doi = {10.1021/acs.nanolett.2c01549}, volume = {22}, year = {2022}, } @article{13996, abstract = {We report the observation of an anomalous nonlinear optical response of the prototypical three-dimensional topological insulator bismuth selenide through the process of high-order harmonic generation. We find that the generation efficiency increases as the laser polarization is changed from linear to elliptical, and it becomes maximum for circular polarization. With the aid of a microscopic theory and a detailed analysis of the measured spectra, we reveal that such anomalous enhancement encodes the characteristic topology of the band structure that originates from the interplay of strong spin–orbit coupling and time-reversal symmetry protection. The implications are in ultrafast probing of topological phase transitions, light-field driven dissipationless electronics, and quantum computation.}, author = {Baykusheva, Denitsa Rangelova and Chacón, Alexis and Lu, Jian and Bailey, Trevor P. and Sobota, Jonathan A. and Soifer, Hadas and Kirchmann, Patrick S. and Rotundu, Costel and Uher, Ctirad and Heinz, Tony F. and Reis, David A. and Ghimire, Shambhu}, issn = {1530-6992}, journal = {Nano Letters}, keywords = {Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}, number = {21}, pages = {8970--8978}, publisher = {American Chemical Society}, title = {{All-optical probe of three-dimensional topological insulators based on high-harmonic generation by circularly polarized laser fields}}, doi = {10.1021/acs.nanolett.1c02145}, volume = {21}, year = {2021}, } @article{10866, abstract = {Recent discoveries have shown that, when two layers of van der Waals (vdW) materials are superimposed with a relative twist angle between them, the electronic properties of the coupled system can be dramatically altered. Here, we demonstrate that a similar concept can be extended to the optics realm, particularly to propagating phonon polaritons–hybrid light-matter interactions. To do this, we fabricate stacks composed of two twisted slabs of a vdW crystal (α-MoO3) supporting anisotropic phonon polaritons (PhPs), and image the propagation of the latter when launched by localized sources. Our images reveal that, under a critical angle, the PhPs isofrequency curve undergoes a topological transition, in which the propagation of PhPs is strongly guided (canalization regime) along predetermined directions without geometric spreading. These results demonstrate a new degree of freedom (twist angle) for controlling the propagation of polaritons at the nanoscale with potential for nanoimaging, (bio)-sensing, or heat management.}, author = {Duan, Jiahua and Capote-Robayna, Nathaniel and Taboada-Gutiérrez, Javier and Álvarez-Pérez, Gonzalo and Prieto Gonzalez, Ivan and Martín-Sánchez, Javier and Nikitin, Alexey Y. and Alonso-González, Pablo}, issn = {1530-6992}, journal = {Nano Letters}, keywords = {Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}, number = {7}, pages = {5323--5329}, publisher = {American Chemical Society}, title = {{Twisted nano-optics: Manipulating light at the nanoscale with twisted phonon polaritonic slabs}}, doi = {10.1021/acs.nanolett.0c01673}, volume = {20}, year = {2020}, } @article{7663, abstract = {Wood, as the most abundant carbon dioxide storing bioresource, is currently driven beyond its traditional use through creative innovations and nanotechnology. For many properties the micro- and nanostructure plays a crucial role and one key challenge is control and detection of chemical and physical processes in the confined microstructure and nanopores of the wooden cell wall. In this study, correlative Raman and atomic force microscopy show high potential for tracking in situ molecular rearrangement of wood polymers during compression. More water molecules (interpreted as wider cellulose microfibril distances) and disentangling of hemicellulose chains are detected in the opened cell wall regions, whereas an increase of lignin is revealed in the compressed areas. These results support a new more “loose” cell wall model based on flexible lignin nanodomains and advance our knowledge of the molecular reorganization during deformation of wood for optimized processing and utilization.}, author = {Felhofer, Martin and Bock, Peter and Singh, Adya and Prats Mateu, Batirtze and Zirbs, Ronald and Gierlinger, Notburga}, issn = {1530-6992}, journal = {Nano Letters}, number = {4}, pages = {2647--2653}, publisher = {American Chemical Society}, title = {{Wood deformation leads to rearrangement of molecules at the nanoscale}}, doi = {10.1021/acs.nanolett.0c00205}, volume = {20}, year = {2020}, } @article{8203, abstract = {Using inelastic cotunneling spectroscopy we observe a zero field splitting within the spin triplet manifold of Ge hut wire quantum dots. The states with spin ±1 in the confinement direction are energetically favored by up to 55 μeV compared to the spin 0 triplet state because of the strong spin–orbit coupling. The reported effect should be observable in a broad class of strongly confined hole quantum-dot systems and might need to be considered when operating hole spin qubits.}, author = {Katsaros, Georgios and Kukucka, Josip and Vukušić, Lada and Watzinger, Hannes and Gao, Fei and Wang, Ting and Zhang, Jian-Jun and Held, Karsten}, issn = {1530-6992}, journal = {Nano Letters}, number = {7}, pages = {5201--5206}, publisher = {American Chemical Society}, title = {{Zero field splitting of heavy-hole states in quantum dots}}, doi = {10.1021/acs.nanolett.0c01466}, volume = {20}, year = {2020}, } @article{17902, abstract = {Probing structural changes of a molecule induced by charge transfer is important for understanding the physicochemical properties of molecules and developing new electronic devices. Here, we interrogate the structural changes of a single diketopyrrolopyrrole (DPP) molecule induced by charge transport at a high bias using scanning tunneling microscope break junction (STM-BJ) techniques. Specifically, we demonstrate that application of a high bias increases the average nonresonant conductance of single Au–DPP–Au junctions. We infer from the increased conductance that resonant charge transport induces planarization of the molecular backbone. We further show that this conformational planarization is assisted by thermally activated junction reorganization. The planarization only occurs under specific electronic conditions, which we rationalize by ab initio calculations. These results emphasize the need for a comprehensive view of single-molecule junctions which includes both the electronic properties and structure of the molecules and the electrodes when designing electrically driven single-molecule motors.}, author = {Zang, Yaping and Fung, E-Dean and Fu, Tianren and Ray, Suman and Garner, Marc H. and Borges, Anders and Steigerwald, Michael L. and Patil, Satish and Solomon, Gemma and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {1}, pages = {673--679}, publisher = {American Chemical Society}, title = {{Voltage-induced single-molecule junction planarization}}, doi = {10.1021/acs.nanolett.0c04260}, volume = {21}, year = {2020}, } @article{17903, abstract = {Light emission from tunnel junctions are a potential photon source for nanophotonic applications. Surprisingly, the photons emitted can have energies exceeding the energy supplied to the electrons by the bias. Three mechanisms for generating these so-called overbias photons have been proposed, but the relationship between these mechanisms has not been clarified. In this work, we argue that multielectron processes provide the best framework for understanding overbias light emission in tunnel junctions. Experimentally, we demonstrate for the first time that the superlinear dependence of emission on conductance predicted by this theory is robust to the temperature of the tunnel junction, indicating that tunnel junctions are a promising candidate for electrically driven broadband photon sources.}, author = {Fung, E-Dean and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {12}, pages = {8912--8918}, publisher = {American Chemical Society}, title = {{Too cool for blackbody radiation: Overbias photon emission in ambient STM due to multielectron processes}}, doi = {10.1021/acs.nanolett.0c03994}, volume = {20}, year = {2020}, } @article{17906, abstract = {One-dimensional sp-hybridized carbon wires, including cumulenes and polyynes, can be regarded as finite versions of carbynes. They are likely to be good candidates for molecular-scale conducting wires as they are predicted to have a high-conductance. In this study, we first characterize the single-molecule conductance of a series of cumulenes and polyynes with a backbone ranging in length from 4 to 8 carbon atoms, including [7]cumulene, the longest cumulenic carbon wire studied to date for molecular electronics. We observe different length dependence of conductance when comparing these two forms of carbon wires. Polyynes exhibit conductance decays with increasing molecular length, while cumulenes show a conductance increase with increasing molecular length. Their distinct conducting behaviors are attributed to their different bond length alternation, which is supported by theoretical calculations. This study confirms the long-standing theoretical predictions on sp-hybridized carbon wires and demonstrates that cumulenes can form highly conducting molecular wires.}, author = {Zang, Yaping and Fu, Tianren and Zou, Qi and Ng, Fay and Li, Hexing and Steigerwald, Michael L. and Nuckolls, Colin and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {11}, pages = {8415--8419}, publisher = {American Chemical Society}, title = {{Cumulene wires display increasing conductance with increasing length}}, doi = {10.1021/acs.nanolett.0c03794}, volume = {20}, year = {2020}, } @article{17908, abstract = {Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted some interest as functional elements of molecular-scale devices. Here we investigate the impact of the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction conductance. Measurements indicate that the conductance of the ferrocene derivative, which is suppressed by 2 orders of magnitude as compared to a fully conjugated analogue, can be modulated by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects of the Fano type that arise from the hybridization of localized metal-based d-orbitals and the delocalized ligand-based π-system. By rotation of the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.}, author = {Camarasa-Gómez, María and Hernangómez-Pérez, Daniel and Inkpen, Michael S. and Lovat, Giacomo and Fung, E-Dean and Roy, Xavier and Venkataraman, Latha and Evers, Ferdinand}, issn = {1530-6992}, journal = {Nano Letters}, number = {9}, pages = {6381--6386}, publisher = {American Chemical Society}, title = {{Mechanically tunable quantum interference in ferrocene-based single-molecule junctions}}, doi = {10.1021/acs.nanolett.0c01956}, volume = {20}, year = {2020}, }