Quantum Transport in Bismuth Two-dimensional Electron System

Two-dimensional electron systems (2DESs) have represented an ever-expanding frontier in condensed matter physics. Over the past two decades, this growth has primarily been propelled by the emergence of novel 2DESs, exemplified by graphene and other two-dimensional crystals, each demonstrating distinctive properties. In this talk, I'll present our recent observation of a high-mobility 2DES on the surface of thin bismuth crystal, which we synthesize via van der Waals epitaxy on hexagonal boron nitride (hBN) flakes. The bismuth 2DES is characterized by its strong spin-orbit coupling (SOC) and harbors both electrons and holes. The simultaneous presence of both carrier types offers a unique opportunity to study the interplay between electron and hole states in the extreme quantum limit; we observe clear signs of charge migration between these states under strong external magnetic fields up to 40 Tesla. The strong magnetic field additionally reveals symmetry breaking in bismuth 2DES, which manifests as splitting of the hole levels. These findings open the door for further exploring potential topological quantum effects in this strongly spin-orbit coupled, high mobility 2DES.