Strongly Anisotropic Spin and Orbital Rashba Effect at a Tellurium - Noble Metal Interface

TL;DR

This study investigates the highly anisotropic Rashba spin-orbit effect at a tellurium-noble metal interface, revealing how lattice symmetry and broken inversion symmetry lead to a strongly modulated spin splitting.

Contribution

It demonstrates the emergence of a highly anisotropic orbital Rashba effect at a Te-Au interface, combining experimental and theoretical analysis to elucidate the underlying symmetry mechanisms.

Findings

Observation of anisotropic Rashba spin-orbit splitting at the Te-Au interface

Identification of symmetry-enforced orbital Rashba effect

Strong modulation of spin splitting by lattice symmetry

Abstract

We study the interplay of lattice, spin and orbital degrees of freedom in a two-dimensional model system: a flat square lattice of Te atoms on a Au(100) surface. The atomic structure of the Te monolayer is determined by scanning tunneling microscopy (STM) and quantitative low-energy electron diffraction (LEED-IV). Using spin- and angle-resolved photoelectron spectroscopy (ARPES) and density functional theory (DFT), we observe a Te-Au interface state with highly anisotropic Rashba-type spin-orbit splitting at the X point of the Brillouin zone. Based on a profound symmetry and tight-binding analysis, we show how in-plane square lattice symmetry and broken inversion symmetry at the Te-Au interface together enforce a remarkably anisotropic orbital Rashba effect which strongly modulates the spin splitting.