Edge mode percolation and equilibration in the topological insulator cadmium arsenide

Journal Article · 20 November 2023 · npj Quantum Materials

DOI: https://doi.org/10.1038/s41535-023-00602-6 · OSTI ID:2217407

Munyan, Simon ; Guo, Binghao ; Huynh, William; Huang, Victor; Stemmer, Susanne

Abstract Two-dimensional topological insulators can feature one-dimensional charge transport via edge modes, which offer a rich ground for studying exotic quasi-particles and for quantum materials applications. In this work, we use lateral junction devices, defined by nanoscale finger gates, to study edge mode transport in the two-dimensional topological insulator Cd ₃ As ₂ . The finger gate can be tuned to transmit an integer number of quantum Hall edge modes and exhibits full equilibration in the bipolar regime. When the Fermi level of the channel crosses a Landau level, reflected modes percolate through the channel, resulting in an anomalous conductance peak. The device does not fully pinch off when the channel is tuned into the topological gap, which is a sign of remnant modes in the channel. These modes are expected from band inversion, while residual bulk conduction associated with the disorder potential may also play a role.

• Research Organization: University of California, Santa Barbara, CA (United States)
• Sponsoring Organization: National Science Foundation (NSF); Office of Naval Research; USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 2217407
• Journal Information: npj Quantum Materials, Journal Name: npj Quantum Materials Journal Issue: 1 Vol. 8; ISSN 2397-4648
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United Kingdom
• Language: English