Observation of Landau quantization and standing waves in HfSiS

TL;DR

This study uses scanning tunneling microscopy and spectroscopy to investigate the Landau quantization and standing waves in HfSiS, revealing its Dirac semimetal properties and Rashba-split surface states with a quasi-linear dispersion.

Contribution

It provides the first detailed experimental characterization of Landau levels and standing waves in HfSiS, linking surface state properties with theoretical calculations.

Findings

Rashba-split surface states exhibit Landau quantization.

Surface states show quasi-linear dispersion.

Interplay between surface states, defects, and collective modes.

Abstract

Recently, HfSiS was found to be a new type of Dirac semimetal with a line of Dirac nodes in the band structure. Meanwhile, Rashba-split surface states are also pronounced in this compound. Here we report a systematic study of HfSiS by scanning tunneling microscopy/spectroscopy at low temperature and high magnetic field. The Rashba-split surface states are characterized by measuring Landau quantization and standing waves, which reveal a quasi-linear dispersive band structure. First-principles calculations based on density-functional theory are conducted and compared with the experimental results. Based on these investigations, the properties of the Rashba-split surface states and their interplay with defects and collective modes are discussed.