Department of Physics & Astronomy

Understanding the strongly correlated features of the electronic structure in twisted bilayer graphene from the pseudo Landau level picture

August 26, 2022l Hit 229
Date : December 7, 2022 16:00 ~
Speaker : Xi Dai (HKUST (홍콩과학기술대학교 물리학과))
Professor : Prof. Dohun Kim, Prof. Sunghoon Jung
Location : 56동105호 +온라인 중계 (코로나 방역 상황에 따라 변동 가능)
In the present seminar, I will introduce how the flat bands in the magic angle twisted bilayer graphene (MATBG) can be understood from the zeroth Landau levels under the twisting generated pseudo magnetic field.  These  pseudo Landau level wave functions are almost the exact Eigen solutions of the real space Hamiltonian around the AA stacking center and can be further viewed as the analog of the  “atomic core level” states in the band structure calculations for the ordinary crystals. In addition, we can use the pseudo zeroth Landau level (PZLL) and the “orthogonalised plane waves” (OPW) made from the PZLL as the two types of basis functions to efficiently reconstruct the entire Moire band structure. Using these PZLL and OPW basis functions, we can describe both the localised and itinerant components in the Moire bands of MATBG and map the MATBG to a “heavy fermion” like system, which can be used to study the orbital magnetism, topology and strongly correlation physics in MATBG.