2024/01/26 by Fernando Peñaranda, Peñaranda, Fernando, Héctor Ochoa +3 · 2 citations
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Metamaterials and Metasurfaces Applications #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.2401.15005
openalex publication_date 2024/01/26 · openalex created_date 2024/01/31 · openalex updated_date 2026/07/28
The chiral lattice structure of twisted bilayer graphene with D6 symmetry allows for intrinsic photogalvanic effects only at off-normal incidence, while additional extrinsic effects are known to be induced by a substrate or a gate potential. In this work, we first compute the intrinsic effects and show they reverse sign at the magic angle, revealing a band inversion at the Γ point. We next consider different extrinsic effects, showing how they can be used to track the strengths of the substrate coupling or displacement field. We also show that the approximate particle-hole symmetry implies stringent constraints on the chemical potential dependence of all photocurrents. A detailed comparison of intrinsic vs. extrinsic photocurrents therefore reveals a wealth of information about the band structure and can also serve as a benchmark to constrain the symmetry breaking patterns of correlated states.