2020/02/29 by Ying Su, Shi-Zeng Lin, Shi‐Zeng Lin
Materials Science · Physics and Astronomy · #Bilayer #Bilayer graphene #Condensed matter physics #Conductance #Current (fluid) #Electrical resistivity and conductivity #Graphene #Graphene research and applications #Hall conductivity #Hall effect #Materials science #Membrane #Nanotechnology #Physics #Quantum and electron transport phenomena #Quantum mechanics #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.125.226401
published as Phys. Rev. Lett. 125, 226401 (2020) · 10 pages and 11 figures
arxiv created 2020/11/24 · openalex publication_date 2020/11/24 · arxiv updated 2020/11/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
It is observed experimentally that the sign of the Hall resistance can be flipped by a dc electric current in the twisted bilayer graphene (TBG) at 3/4 filling of the fourfold degenerate conduction flat bands. The experiment implies a switching of the valley polarization (VP) and topology in TBG. Here we present a theory on the current-induced switching of VP and topology. The presence of current in the bulk causes the redistribution of electron occupation in bands near the Fermi energy, which then deforms and shifts the band dispersion due to the Coulomb interaction. Above a critical current, the original occupied and empty bands can be swapped, resulting in the switching of VP and topology.