Scanning tunneling microscopy on cleaved Mn3Sn(0001) surface

Hung-Hsiang Yang,Agustinus Nugroho,Satoru Nakatsuji,Muhammad Ikhlas,Yukio Hasegawa,Yasuo Yoshida,Takahiro Tomita,Taisuke Ozaki,Chi-Cheng Lee

doi:10.1038/s41598-019-45958-7

Abstract

We have studied in-situ cleaved (0001) surfaces of the magnetic Weyl semimetal Mn3Sn by low-temperature scanning tunneling microscopy and spectroscopy (STM/S). It was found that freshly cleaved Mn3Sn surfaces are covered with unknown clusters, and the application of voltage pulses in the tunneling condition was needed to achieve atomically flat surfaces. STM topographs taken on the flat terrace show a bulk-terminated 1 × 1 honeycomb lattice with the Sn site brightest. First-principles calculations reveal that the brightest contrast at the Sn site originates from the surrounding surface Mn d orbitals. Tunneling spectroscopy performed on the as-cleaved and voltage-pulsed surfaces show a prominent semimetal valley near the Fermi energy.

Highlights

We have studied in-situ cleaved (0001) surfaces of the magnetic Weyl semimetal Mn3Sn by lowtemperature scanning tunneling microscopy and spectroscopy (STM/S)
STM topographs taken on the flat terrace show a bulk-terminated 1 × 1 honeycomb lattice with the Sn site brightest
The absence of atomically flat terrace on cleaved Mn3Sn surfaces was reported in a previou report[8]

Summary

Introduction

We have studied in-situ cleaved (0001) surfaces of the magnetic Weyl semimetal Mn3Sn by lowtemperature scanning tunneling microscopy and spectroscopy (STM/S). It was found that freshly cleaved Mn3Sn surfaces are covered with unknown clusters, and the application of voltage pulses in the tunneling condition was needed to achieve atomically flat surfaces. Tunneling spectroscopy performed on the as-cleaved and voltage-pulsed surfaces show a prominent semimetal valley near the Fermi energy. The atomic structure of voltage-pulsed flat surfaces was confirmed as a bulk-terminated one through the careful analysis of the atomic lattices of adjacent terraces and first-principles calculations. To address the electronic structure, we performed tunneling spectroscopy on freshly-cleaved and voltage-pulsed surfaces. Both measurements revealed a semimetallic valley shape and shared a similar minimum near the Fermi level in the tunneling conductance (dI/dV) spectra. The valley was found to be composed of two peaks that arise from Mn d states

Methods

Results

Conclusion