Out-of-plane transport in ZrSiS and ZrSiSe microstructures

Kent R. Shirer,Kimberly A. Modic,Tino Zimmerling,Markus König,Andrew P. Mackenzie,Leslie Schoop,Philip J. W. Moll,Maja D. Bachmann

doi:10.1063/1.5124568

Abstract

A recent class of topological nodal-line semimetals with the general formula MSiX (M = Zr, Hf and X = S, Se, Te) has attracted much experimental and theoretical interest due to their properties, particularly their large magnetoresistances and high carrier mobilities. The plateletlike nature of the MSiX crystals and their extremely low residual resistivities make measurements of the resistivity along the [001] direction extremely challenging. To accomplish such measurements, microstructures of single crystals were prepared using focused ion beam techniques. Microstructures prepared in this manner have very well-defined geometries and maintain their high crystal quality, verified by the observations of quantum oscillations. We present magnetoresistance and quantum oscillation data for currents applied along both [001] and [100] in ZrSiS and ZrSiSe, which are consistent with the nontrivial topology of the Dirac line-node, as determined by a measured π Berry phase. Surprisingly, we find that, despite the three dimensional nature of both the Fermi surfaces of ZrSiS and ZrSiSe, both the resistivity anisotropy under applied magnetic fields and the in-plane angular dependent magnetoresistance differ considerably between the two compounds. Finally, we discuss the role microstructuring can play in the study of these materials and our ability to make these microstructures free-standing.

Highlights

We present magnetoresistance and quantum oscillation data for currents applied along both [001] and [100] in ZrSiS and ZrSiSe, which are consistent with the nontrivial topology of the Dirac line-node, as determined by a measured π Berry phase
The first is the strong difference in resistivity anisotropy between ZrSiS and ZrSiSe under applied magnetic fields
In the absence of magnetic field, the resistivity anisotropy in both compounds is moderate, ∼8 and ∼4, for ZrSiS and ZrSiSe, respectively, and does not vary substantially with temperature

Summary

Introduction

Materials which exhibit nontrivial topology or linear dispersion relations in their band structures such as topological insulators, graphene, and Dirac and Weyl semimetals have attracted intense interest in the past 15 years for their exotic properties, potential technological applications, and possible topological superconductivity.. A class of topological materials which host Dirac band crossings along nodal lines or loops, distinct from the discrete Dirac points of Dirac and Weyl semimetals, have been predicted and discovered, and resulting experimental and theoretical studies have demonstrated these materials to be excellent candidates for both application and the study of new, novel physics. Dirac node, where the nodal-lines are located near the Fermi level, and its linearly dispersing bands extend over a large energy range (0–2 eV).. The physics of the material is thought to be determined by the nodal-line states.. The physics of the material is thought to be determined by the nodal-line states. the ZrSiX-type materials provide a testing ground to explore the scitation.org/journal/apm relationship between dimensionality of the Fermi surface and the topological character of the materials

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