---
OA_type: closed access
_id: '21765'
abstract:
- lang: eng
text: "Dielectric particles of the same material exchange electrical charge during
collisions or sliding contacts, yet the underlying charge-exchange mechanism is
still not understood. The fact that particles can become highly charged as a result
of this effect has significant consequences for many settings, both in nature
and industry, such as thunderstorms, volcanic eruptions, particle aggregation
during meteorite and planet formation, and the clogging of industrial granular
systems. Toward understanding these systems, great efforts have been made to develop
precise in situ measurements for particle charge, e.g., to determine ensemble
charge distributions or measure exchange during individual contacts. Here, we
present experimental results concerning the particle size scaling of the stationary-state
charge distributions of oxide particles in the sub-millimeter range. We measure
the charge distributions for large ensembles of monodisperse ZrO2:SiO2 composite
spheres, ranging from 172 to 545µm in diameter. These distributions are non-Gaussian
and collapse to a single master curve when plotted as functions of the surface
charge density Σ=\U0001D45E/4\U0001D70B\U0001D4452. X-ray fluorescence and atomic
force microscopy measurements show that the differences in the measured charge
distributions are not due to variations in chemical composition or surface roughness,
but rather to size alone. Our findings provide constraints on microscopic models
for charge exchange, namely that they should lead to steady-state distributions
that are non-Gaussian and scale in a specific way with particle size."
acknowledgement: This research was supported by ANID Grants QUIMAL No. 160001, FONDECYT
No. 1221597, and FONDEQUIP No. EQM190177. The authors thank Rodrigo Espinoza for
the EDS-SEM measurements and Domingo Jullian for fruitful discussions. We also acknowledge
the technical assistance of Ricardo Silva and Andrés Espinosa at DFI, FCFM, Universidad
de Chile.
article_number: '045604'
article_processing_charge: No
article_type: original
author:
- first_name: Macarena
full_name: Lara, Macarena
last_name: Lara
- first_name: Marcos
full_name: Flores, Marcos
last_name: Flores
- first_name: Gustavo
full_name: Castillo, Gustavo
last_name: Castillo
- first_name: Santiago
full_name: Tassara, Santiago
last_name: Tassara
- first_name: Scott R
full_name: Waitukaitis, Scott R
id: 3A1FFC16-F248-11E8-B48F-1D18A9856A87
last_name: Waitukaitis
orcid: 0000-0002-2299-3176
- first_name: Nicolás
full_name: Mujica, Nicolás
last_name: Mujica
citation:
ama: Lara M, Flores M, Castillo G, Tassara S, Waitukaitis SR, Mujica N. Particle
size scaling of non-Gaussian granular charge distributions. Physical Review
Materials. 2026;10(4). doi:10.1103/qw6t-xqdw
apa: Lara, M., Flores, M., Castillo, G., Tassara, S., Waitukaitis, S. R., &
Mujica, N. (2026). Particle size scaling of non-Gaussian granular charge distributions.
Physical Review Materials. American Physical Society. https://doi.org/10.1103/qw6t-xqdw
chicago: Lara, Macarena, Marcos Flores, Gustavo Castillo, Santiago Tassara, Scott
R Waitukaitis, and Nicolás Mujica. “Particle Size Scaling of Non-Gaussian Granular
Charge Distributions.” Physical Review Materials. American Physical Society,
2026. https://doi.org/10.1103/qw6t-xqdw.
ieee: M. Lara, M. Flores, G. Castillo, S. Tassara, S. R. Waitukaitis, and N. Mujica,
“Particle size scaling of non-Gaussian granular charge distributions,” Physical
Review Materials, vol. 10, no. 4. American Physical Society, 2026.
ista: Lara M, Flores M, Castillo G, Tassara S, Waitukaitis SR, Mujica N. 2026. Particle
size scaling of non-Gaussian granular charge distributions. Physical Review Materials.
10(4), 045604.
mla: Lara, Macarena, et al. “Particle Size Scaling of Non-Gaussian Granular Charge
Distributions.” Physical Review Materials, vol. 10, no. 4, 045604, American
Physical Society, 2026, doi:10.1103/qw6t-xqdw.
short: M. Lara, M. Flores, G. Castillo, S. Tassara, S.R. Waitukaitis, N. Mujica,
Physical Review Materials 10 (2026).
date_created: 2026-04-26T22:01:47Z
date_published: 2026-04-01T00:00:00Z
date_updated: 2026-04-28T07:13:56Z
day: '01'
department:
- _id: ScWa
doi: 10.1103/qw6t-xqdw
fulldoi: https://doi.org/10.1103/qw6t-xqdw
intvolume: ' 10'
issue: '4'
language:
- iso: eng
month: '04'
oa_version: None
publication: Physical Review Materials
publication_identifier:
eissn:
- 2475-9953
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Particle size scaling of non-Gaussian granular charge distributions
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 10
year: '2026'
...
---
_id: '17476'
abstract:
- lang: eng
text: "Lead halide perovskites have recently been reported to demonstrate an exceptionally
high nonlinear (Kerr) refractive index n2 of up to 10−8cm2/W in CH3NH3PbBr3.
Other researchers, however, observe different, substantially more conservative
numbers. In order to resolve this disagreement, the nonlinear Kerr index of a
bulk sample of lead halide perovskite was measured directly by means of an interferometer.
This approach has many advantages as compared to the more standard z-scan technique.
In particular, this method allows studying the induced changes to the refractive
index in a time-resolved manner, thus enabling to separate the different contributions
to \U0001D45B2. The extracted \U0001D45B2 values for CsPbBr3 and MAPbBr3 at \U0001D706≈1µm
are \U0001D45B2=+2.1×10−14cm2/W and \U0001D45B2=+6×10−15cm2/W, respectively. Hence,
these values are substantially lower than what has been indicated in most of the
previous reports, implying the latter one should be regarded with great care."
acknowledgement: "We gratefully acknowledge the assistance of Prof. John\r\nDudley."
article_number: '085403'
article_processing_charge: No
article_type: original
author:
- first_name: Dusan
full_name: Lorenc, Dusan
id: 40D8A3E6-F248-11E8-B48F-1D18A9856A87
last_name: Lorenc
- first_name: Ayan
full_name: Zhumekenov, Ayan
last_name: Zhumekenov
- first_name: Osman M.
full_name: Bakr, Osman M.
last_name: Bakr
- first_name: Zhanybek
full_name: Alpichshev, Zhanybek
id: 45E67A2A-F248-11E8-B48F-1D18A9856A87
last_name: Alpichshev
orcid: 0000-0002-7183-5203
citation:
ama: 'Lorenc D, Zhumekenov A, Bakr OM, Alpichshev Z. No extraordinary χ(3) in lead-halide
perovskites: Placing an upper bound on Kerr nonlinearity by means of time-resolved
interferometry. Physical Review Materials. 2024;8(8). doi:10.1103/PhysRevMaterials.8.085403'
apa: 'Lorenc, D., Zhumekenov, A., Bakr, O. M., & Alpichshev, Z. (2024). No extraordinary
χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by
means of time-resolved interferometry. Physical Review Materials. American
Physical Society. https://doi.org/10.1103/PhysRevMaterials.8.085403'
chicago: 'Lorenc, Dusan, Ayan Zhumekenov, Osman M. Bakr, and Zhanybek Alpichshev.
“No Extraordinary χ(3) in Lead-Halide Perovskites: Placing an Upper Bound on Kerr
Nonlinearity by Means of Time-Resolved Interferometry.” Physical Review Materials.
American Physical Society, 2024. https://doi.org/10.1103/PhysRevMaterials.8.085403.'
ieee: 'D. Lorenc, A. Zhumekenov, O. M. Bakr, and Z. Alpichshev, “No extraordinary
χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by
means of time-resolved interferometry,” Physical Review Materials, vol.
8, no. 8. American Physical Society, 2024.'
ista: 'Lorenc D, Zhumekenov A, Bakr OM, Alpichshev Z. 2024. No extraordinary χ(3)
in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by means
of time-resolved interferometry. Physical Review Materials. 8(8), 085403.'
mla: 'Lorenc, Dusan, et al. “No Extraordinary χ(3) in Lead-Halide Perovskites: Placing
an Upper Bound on Kerr Nonlinearity by Means of Time-Resolved Interferometry.”
Physical Review Materials, vol. 8, no. 8, 085403, American Physical Society,
2024, doi:10.1103/PhysRevMaterials.8.085403.'
short: D. Lorenc, A. Zhumekenov, O.M. Bakr, Z. Alpichshev, Physical Review Materials
8 (2024).
corr_author: '1'
date_created: 2024-09-01T22:01:08Z
date_published: 2024-08-23T00:00:00Z
date_updated: 2025-09-08T09:06:34Z
day: '23'
department:
- _id: ZhAl
doi: 10.1103/PhysRevMaterials.8.085403
external_id:
isi:
- '001299497800001'
fulldoi: https://doi.org/10.1103/PhysRevMaterials.8.085403
intvolume: ' 8'
isi: 1
issue: '8'
language:
- iso: eng
month: '08'
oa_version: None
publication: Physical Review Materials
publication_identifier:
eissn:
- 2475-9953
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'No extraordinary χ(3) in lead-halide perovskites: Placing an upper bound on
Kerr nonlinearity by means of time-resolved interferometry'
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 8
year: '2024'
...
---
_id: '12109'
abstract:
- lang: eng
text: Kelvin probe force microscopy (KPFM) is a powerful tool for studying contact
electrification (CE) at the nanoscale, but converting KPFM voltage maps to charge
density maps is nontrivial due to long-range forces and complex system geometry.
Here we present a strategy using finite-element method (FEM) simulations to determine
the Green's function of the KPFM probe/insulator/ground system, which allows us
to quantitatively extract surface charge. Testing our approach with synthetic
data, we find that accounting for the atomic force microscope (AFM) tip, cone,
and cantilever is necessary to recover a known input and that existing methods
lead to gross miscalculation or even the incorrect sign of the underlying charge.
Applying it to experimental data, we demonstrate its capacity to extract realistic
surface charge densities and fine details from contact-charged surfaces. Our method
gives a straightforward recipe to convert qualitative KPFM voltage data into quantitative
charge data over a range of experimental conditions, enabling quantitative CE
at the nanoscale.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
- _id: ScienComp
acknowledgement: "This project has received funding from the European Research Council
(ERC) under the European Union’s Horizon 2020 research and innovation programme
(Grant Agreement\r\nNo. 949120). This research was supported by the Scientific Service
Units of the Institute of Science and Technology Austria (ISTA) through resources
provided by the Miba Machine\r\nShop, the Nanofabrication Facility, and the Scientific
Computing Facility. We thank F. Stumpf from Park Systems for useful discussions
and support with scanning probe microscopy.\r\nF.P. and J.C.S. contributed equally
to this work."
article_number: '125605'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Felix
full_name: Pertl, Felix
id: 6313aec0-15b2-11ec-abd3-ed67d16139af
last_name: Pertl
orcid: 0000-0003-0463-5794
- first_name: Juan Carlos A
full_name: Sobarzo Ponce, Juan Carlos A
id: 4B807D68-AE37-11E9-AC72-31CAE5697425
last_name: Sobarzo Ponce
- first_name: Lubuna B
full_name: Shafeek, Lubuna B
id: 3CD37A82-F248-11E8-B48F-1D18A9856A87
last_name: Shafeek
orcid: 0000-0001-7180-6050
- first_name: Tobias
full_name: Cramer, Tobias
last_name: Cramer
- first_name: Scott R
full_name: Waitukaitis, Scott R
id: 3A1FFC16-F248-11E8-B48F-1D18A9856A87
last_name: Waitukaitis
orcid: 0000-0002-2299-3176
citation:
ama: Pertl F, Sobarzo Ponce JCA, Shafeek LB, Cramer T, Waitukaitis SR. Quantifying
nanoscale charge density features of contact-charged surfaces with an FEM/KPFM-hybrid
approach. Physical Review Materials. 2022;6(12). doi:10.1103/PhysRevMaterials.6.125605
apa: Pertl, F., Sobarzo Ponce, J. C. A., Shafeek, L. B., Cramer, T., & Waitukaitis,
S. R. (2022). Quantifying nanoscale charge density features of contact-charged
surfaces with an FEM/KPFM-hybrid approach. Physical Review Materials. American
Physical Society. https://doi.org/10.1103/PhysRevMaterials.6.125605
chicago: Pertl, Felix, Juan Carlos A Sobarzo Ponce, Lubuna B Shafeek, Tobias Cramer,
and Scott R Waitukaitis. “Quantifying Nanoscale Charge Density Features of Contact-Charged
Surfaces with an FEM/KPFM-Hybrid Approach.” Physical Review Materials.
American Physical Society, 2022. https://doi.org/10.1103/PhysRevMaterials.6.125605.
ieee: F. Pertl, J. C. A. Sobarzo Ponce, L. B. Shafeek, T. Cramer, and S. R. Waitukaitis,
“Quantifying nanoscale charge density features of contact-charged surfaces with
an FEM/KPFM-hybrid approach,” Physical Review Materials, vol. 6, no. 12.
American Physical Society, 2022.
ista: Pertl F, Sobarzo Ponce JCA, Shafeek LB, Cramer T, Waitukaitis SR. 2022. Quantifying
nanoscale charge density features of contact-charged surfaces with an FEM/KPFM-hybrid
approach. Physical Review Materials. 6(12), 125605.
mla: Pertl, Felix, et al. “Quantifying Nanoscale Charge Density Features of Contact-Charged
Surfaces with an FEM/KPFM-Hybrid Approach.” Physical Review Materials,
vol. 6, no. 12, 125605, American Physical Society, 2022, doi:10.1103/PhysRevMaterials.6.125605.
short: F. Pertl, J.C.A. Sobarzo Ponce, L.B. Shafeek, T. Cramer, S.R. Waitukaitis,
Physical Review Materials 6 (2022).
corr_author: '1'
date_created: 2023-01-08T23:00:53Z
date_published: 2022-12-29T00:00:00Z
date_updated: 2026-08-27T11:42:43Z
day: '29'
department:
- _id: ScWa
- _id: NanoFab
doi: 10.1103/PhysRevMaterials.6.125605
ec_funded: 1
external_id:
arxiv:
- '2209.01889'
isi:
- '000908384800001'
fulldoi: https://doi.org/10.1103/PhysRevMaterials.6.125605
intvolume: ' 6'
isi: 1
issue: '12'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: ' https://doi.org/10.48550/arXiv.2209.01889'
month: '12'
oa: 1
oa_version: Preprint
project:
- _id: 0aa60e99-070f-11eb-9043-a6de6bdc3afa
call_identifier: H2020
grant_number: '949120'
name: 'Tribocharge: a multi-scale approach to an enduring problem in physics'
publication: Physical Review Materials
publication_identifier:
eissn:
- 2475-9953
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
record:
- id: '20203'
relation: dissertation_contains
status: public
- id: '22684'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Quantifying nanoscale charge density features of contact-charged surfaces with
an FEM/KPFM-hybrid approach
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 6
year: '2022'
...