Fock-Darwin states in a circular n-p junction of topological surface states

Jun Zhang, Ye-ping Jiang

Published 2023-01-17Version 1

We analyze and observe the Fock-Darwin (FD) states in a circular n-p junction (CNPJ) of topological surface states. The FD states in the CNPJ are found to have a unique core-shell structure of trapped electrons and holes, the interplay between which is highly tunable by the magnetic field. This leads to the trapping, detrapping and retrapping as well as other exotic behaviors described herein that have no analog in their conventional counterparts. A modified Einstein-Brillouin-Keller method is introduced to derive the FD states semiclassically. Experimentally, we obtain the clearly resolved FD states up to 14 Tesla, visualizing directly the field-dependent potential landscape coming from the electron interactions in a CNPJ at the surface of a three-dimensional topological insulator thin film. Our findings signal the high tunability of the FD states in CNPJs of topological surface states.