Evolution of Weyl orbit and quantum Hall effect in Dirac semimetal Cd3As2

Cheng Zhang,Ju-Hyun Park,Jinglei Zhang,Weiyi Wang,Xiang Yuan,Zhigao Sheng,Shiheng Lu,Enze Zhang,Zhuoliang Ni,Long Cheng,Awadhesh Narayan,Shanshan Liu,Stefano Sanvito,Faxian Xiu,Yanwen Liu,Li Pi,Huiqin Zhang

doi:10.1038/s41467-017-01438-y

Abstract

Owing to the coupling between open Fermi arcs on opposite surfaces, topological Dirac semimetals exhibit a new type of cyclotron orbit in the surface states known as Weyl orbit. Here, by lowering the carrier density in Cd3As2 nanoplates, we observe a crossover from multiple-frequency to single-frequency Shubnikov–de Haas (SdH) oscillations when subjected to out-of-plane magnetic field, indicating the dominant role of surface transport. With the increase of magnetic field, the SdH oscillations further develop into quantum Hall state with non-vanishing longitudinal resistance. By tracking the oscillation frequency and Hall plateau, we observe a Zeeman-related splitting and extract the Landau level index as well as sub-band number. Different from conventional two-dimensional systems, this unique quantum Hall effect may be related to the quantized version of Weyl orbits. Our results call for further investigations into the exotic quantum Hall states in the low-dimensional structure of topological semimetals.

Highlights

Owing to the coupling between open Fermi arcs on opposite surfaces, topological Dirac semimetals exhibit a new type of cyclotron orbit in the surface states known as Weyl orbit
It is noteworthy that Cd3As2 is a Dirac semimetal, which can be viewed as a special Weyl semimetal with opposite Weyl node pairs overlapping in the momentum space[17,19]
We report the evolution of 2D surface transport and quantum Hall effect (QHE) of Dirac semimetals when approaching the quantum limit based on a series of Cd3As2 nanoplates

Summary

Introduction

Owing to the coupling between open Fermi arcs on opposite surfaces, topological Dirac semimetals exhibit a new type of cyclotron orbit in the surface states known as Weyl orbit. By decreasing the Fermi level, we observed a transition from the coexistence of bulk and surface SdH oscillations to surface-dominant transport under out-of-plane magnetic field. By tracking the oscillation frequency and Hall plateau, we observe a Zeeman-related splitting behavior under high field and extract Landau level (LL) index as well as the sub-band number.

Results

Conclusion