Effect of uniaxial stress on the electronic band structure of NbP

Clemens Schindler,Jonathan Noky,Marcus Schmidt,Claudia Felser,Johannes Gooth,Jochen Wosnitza

doi:10.1103/physrevb.102.035132

Abstract

The Weyl semimetal NbP exhibits a very small Fermi surface consisting of two electron and two hole pockets, whose fourfold degeneracy in $k$ space is tied to the rotational symmetry of the underlying tetragonal crystal lattice. By applying uniaxial stress, the crystal symmetry can be reduced, which successively leads to a degeneracy lifting of the Fermi-surface pockets. This is reflected by a splitting of the Shubnikov-de Haas frequencies when the magnetic field is aligned along the $c$ axis of the tetragonal lattice. In this study, we present the measurement of Shubnikov-de Haas oscillations of single-crystalline NbP samples under uniaxial tension, combined with state-of-the-art calculations of the electronic band structure. Our results show qualitative agreement between calculated and experimentally determined Shubnikov-de Haas frequencies, demonstrating the robustness of the band-structure calculations upon introducing strain. Furthermore, we predict a significant shift of the Weyl points with increasing uniaxial tension, allowing for an effective tuning to the Fermi level at only 0.8% of strain along the $a$ axis.

Highlights

The symmetry and topology of electronic band structures in crystalline materials is inherently connected to the symmetry of the underlying crystal lattice
A powerful experimental tool for the exploration of the symmetry dependence of electronic properties is the application of uniaxial stress, as it allows one to reduce the symmetry of the crystal lattice and provides a rather different kind of information than application of hydrostatic pressure
We report on the effect of uniaxial stress on the Fermi surface of NbP, determined via Shubnikov–de Haas (SdH) oscillations in the MR of two single-crystalline NbP samples

Summary

Introduction

The symmetry and topology of electronic band structures in crystalline materials is inherently connected to the symmetry of the underlying crystal lattice. The interest in topological properties of electronic band structures surged, which aroused the interest in studying the uniaxial strain response of materials with remarkable topological band-structure features, using both theoretical [1,2,3,4,5,6,7,8,9,10,11,12] and experimental [13,14,15,16,17] methods One of those materials is the semimetallic transition-metal monopnictide NbP, which has recently stimulated numerous studies [18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36]. Cyclotron masses in the order of 5–15% of the free electron mass m0 and large chargecarrier mobilities in the order of 106–107 cm V−1 s−1 [20]

Methods

Results

Conclusion