Surface Termination Dependent Quasiparticle Scattering Interference and Magneto-transport Study on ZrSiS

TL;DR

This study combines theoretical calculations, STM, and magneto-transport experiments to explore how surface termination influences quasiparticle scattering and electronic properties in ZrSiS, revealing the role of surface orbitals and Dirac line nodes.

Contribution

It provides new insights into surface termination effects on surface and bulk electronic structures in ZrSiS, highlighting the importance of Zr-d orbitals in Dirac line node semimetals.

Findings

Surface termination affects surface bands but not bulk Dirac bands.

Surface and bulk electronic structures are consistent with band calculations.

Magnetoresistance shows a nearly linear H dependence.

Abstract

Dirac nodal line semimetals represent a new state of quantum matters in which the electronic bands touch to form a closed loop with linear dispersion. Here, we report a combined study on ZrSiS by density functional theory calculation, scanning tunneling microscope (STM) and magneto-transport measurements. Our STM measurements reveal the spectroscopic signatures of a diamond-shaped Dirac bulk band and a surface band on two types of cleaved surfaces as well as a spin polarized surface band at ${\bar{\Gamma}}$ at E~0.6eV on S-surface, consistent with our band calculation. Furthermore, we find the surface termination does not affect the surface spectral weight from the Dirac bulk bands but greatly affect the surface bands due to the change in the surface orbital composition. From our magneto-transport measurements, the primary Shubnikov de-Haas frequency is identified to stem from the hole-type quasi-two-dimensional Fermi surface between {\Gamma} and X. The extracted non-orbital magnetoresistance (MR) contribution D($\theta$, H) yields a nearly H-linear dependence, which is attributed to the intrinsic MR in ZrSiS. Our results demonstrate the unique Dirac line nodes phase and the dominating role of Zr-d orbital on the electronic structure in ZrSiS and the related compounds.