Topological charge density waves at half-integer filling of a moiré superlattice
Polshyn, Hryhoriy
Zhang, Y.
Kumar, M. A.
Soejima, T.
Ledwith, P.
Watanabe, K.
Taniguchi, T.
Vishwanath, A.
Zaletel, M. P.
Young, A. F.
general physics
astronomy
When a flat band is partially filled with electrons, strong Coulomb interactions between them may lead to the emergence of topological gapped states with quantized Hall conductivity. Such emergent topological states have been found in partially filled Landau levels1 and Hofstadter bands2,3; however, in both cases, a large magnetic field is required to produce the underlying flat band. The recent observation of quantum anomalous Hall effects in narrow-band moiré materials4,5,6,7 has led to the theoretical prediction that such phases could be realized at zero magnetic field8,9,10,11,12. Here we report the observation of insulators with Chern number C = 1 in the zero-magnetic-field limit at half-integer filling of the moiré superlattice unit cell in twisted monolayer–bilayer graphene7,13,14,15. Chern insulators in a half-filled band suggest the spontaneous doubling of the superlattice unit cell2,3,16, and our calculations find a ground state of the topological charge density wave at half-filling of the underlying band. The discovery of these topological phases at fractional superlattice filling enables the further pursuit of zero-magnetic-field phases that have fractional statistics that exist either as elementary excitations or bound to lattice dislocations.
Springer Nature
2021
info:eu-repo/semantics/article
doc-type:article
text
http://purl.org/coar/resource_type/c_6501
https://research-explorer.ista.ac.at/record/10617
Polshyn H, Zhang Y, Kumar MA, et al. Topological charge density waves at half-integer filling of a moiré superlattice. <i>Nature Physics</i>. 2021. doi:<a href="https://doi.org/10.1038/s41567-021-01418-6">10.1038/s41567-021-01418-6</a>
eng
info:eu-repo/semantics/altIdentifier/doi/10.1038/s41567-021-01418-6
info:eu-repo/semantics/altIdentifier/issn/1745-2473
info:eu-repo/semantics/altIdentifier/issn/1745-2481
info:eu-repo/semantics/altIdentifier/arxiv/2104.01178
info:eu-repo/semantics/openAccess