Magnetotransport Properties of Square-Net Compounds of NbSiSb and NbGeSb Single Crystals

TL;DR

This study synthesizes high-quality single crystals of NbSiSb and NbGeSb, analyzes their anisotropic band structures and magnetotransport properties, and explores their potential as tunable topological semimetals.

Contribution

It provides detailed experimental and theoretical insights into the electronic structures and transport mechanisms of NbSiSb and NbGeSb, expanding the understanding of square-net topological materials.

Findings

Strong anisotropic magnetotransport behaviors observed.

Electron-phonon scattering mechanisms are similar in both compounds.

Band structures can potentially be tuned via element doping.

Abstract

We successfully grew single crystals of Si- and Ge-square-net compounds of NbSiSb and NbGeSb whose excellent crystalline quality are verified using single-crystal x-ray diffraction, rocking curves, scanning and transmission electron microscopies. Since these two compounds share major crystallographic similarity with the topological nodal-line semimetals of ZrSiS family, we employ density functional theory (DFT) calculations and magnetotransport measurements to demonstrate their band structures as well as the electron scattering mechanisms. DFT calculations show that the fermiology shows strong anisotropy from the crystallographic c-axis to the ab-plane and weak anisotropy within the ab plane, which is consistent with the strong anisotropic magnetotransport behaviors. Following the Kohler's scaling rule we prove that similar interband and intraband electron-phonon scattering mechanisms work in both the NbSiSb and NbGeSb compounds. The study of electronic transport mechanism in the presence of external magnetic field renders deep insight into topological behavior together with it's Fermi surface, and the high similarity of crystallography and strong difference in band structures between the present single crystals and that of ZrSiS family provides the possibility to tune the band structure via element doping