Contactless Microwave Detection of Shubnikov–De Haas Oscillations in Three-Dimensional Dirac Semimetal ZrTe5**Supported by the National Key Research and Development Program of China under Grant No 2016YFA0401003, the National Natural Science Foundation of China under Grant Nos 11774353, 11574320, 11374302, 11804340, U1432251 and U1732274, the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology under Grant No

Abstract

We report Shubnikov–de Haas (SdH) oscillations of a three-dimensional (3D) Dirac semimetal candidate of layered material ZrTe5 single crystals through contactless electron spin resonance (ESR) measurements with the magnetic field up to 1.4 T. The ESR signals manifest remarkably anisotropic characteristics with respect to the direction of the magnetic field, indicating an anisotropic Fermi surface in ZrTe5. Further experiments demonstrate that the ZrTe5 single crystals have the signature of massless Dirac fermions with nontrivial π Berry phase, key evidence for 3D Dirac/Weyl fermions. Moreover, the onset of quantum oscillation of our ZrTe5 crystals revealed by the ESR can be derived down to 0.2 T, much smaller than the onset of SdH oscillation determined by conventional magnetoresistance measurements. Therefore, ESR measurement is a powerful tool to study the topologically nontrivial electronic structure in Dirac/Weyl semimetals and other topological materials with low bulk carrier density.