Work

Exact Diagonalization for Magic-Angle Twisted Bilayer Graphene

Year: 2021

Type: article

Abstract: We report on finite-size exact-diagonalization calculations in a Hilbert space defined by the continuum-model flat moiré bands of magic angle twisted bilayer graphene. For moiré band filling 3>|ν|>2, where superconductivity is strongest, we obtain evidence that the ground state is a spin ferromagnet. Near |ν|=3, we find Chern insulator ground states that have spontaneous spin, valley, and sublattice polarization, and demonstrate that the anisotropy energy in this order-parameter space is strongly band-filling-factor dependent. We emphasize that inclusion of the remote band self-energy is necessary for a reliable description of magic angle twisted bilayer graphene flat band correlations.

Source: Physical Review Letters

DOI: 10.1103/physrevlett.127.147203

Authors: Pawel Potasz, Ming Xie, A. H. MacDonald

Institutions: Wrocław University of Science and Technology, The University of Texas at Austin

Language: English

Topic: Graphene research and applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: U.S. Department of Energy, Narodowa Agencja Wymiany Akademickiej, Basic Energy Sciences

Awards: TRANSPORT AND COLLECTIVE PROPERTIES OF SEMICONDUCTORS AND GRAPHEN OVERLAYERS, G222768804, TRANSPORT AND COLLECTIVE PROPERTIES OF DILUTED MAGNETIC SEMICONDUCTOR MULTILAYERS AND NANOSTRUCTURES, MAGNETISM IN MOIRE MATERIALS