Work

Electric field tunable bands in a doubly aligned bilayer graphene hBN moiré superlattice

Year: 2024

Type: article

Abstract: In this paper, we demonstrate electric-field-induced band modification of an asymmetrically twisted doubly aligned bilayer graphene hBN (hBN/BLG/hBN) supermoir\'e lattice. Distinct from unaligned BLG/hBN systems, we observe regions in the density-displacement field $(n\text{\ensuremath{-}}D)$ plane where the device conductance is independent of $n$ and decreases as $|D|$ increases. This distinction arises due to the angle asymmetry between the layers, which induces field-controlled layer polarization. We identify $D$-dependent additional band gaps near the charge neutrality point that appear in the conduction (valence) band for negative (positive) $D$ values. In the quantum Hall regime, different sixfold degenerate Landau levels are observed. Our findings establish that in an asymmetric supermoir\'e heterostructure, an external vertical displacement field affects the valence and conduction bands very differently and sheds light on the asymmetric conductance patterns noted in previous studies.

Source: Physical review. B./Physical review. B

DOI: 10.1103/physrevb.110.235414

Authors: Priya Tiwari, Kenji Watanabe, Takashi Taniguchi, Aveek Bid

Institutions: Weizmann Institute of Science, Indian Institute of Science Bangalore, National Institute for Materials Science

Language: English

Topic: Graphene research and applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: Department of Science and Technology, Ministry of Science and Technology, India, Ministry of Education, Culture, Sports, Science and Technology, Japan Society for the Promotion of Science

Awards: G4806815962, G810057230, G898758523