Orbital-driven Rashba effect in a binary honeycomb monolayer AgTe

TL;DR

This study provides experimental evidence linking the orbital angular momentum in a monolayer AgTe to the Rashba effect, advancing understanding of spin-orbit phenomena in two-dimensional materials.

Contribution

It demonstrates the orbital angular momentum origin of the Rashba effect in a binary honeycomb monolayer, supported by ARPES, 2PPE, LEED, and first-principles calculations.

Findings

Rashba-type spin splittings correlate with orbital angular momentum presence.

Structural parameters of AgTe monolayer determined with picometer accuracy.

Orbital-symmetry analysis confirms the OAM-based origin of Rashba effect.

Abstract

The Rashba effect is fundamental to the physics of two-dimensional electron systems and underlies a variety of spintronic phenomena. It has been proposed that the formation of Rashba-type spin splittings originates microscopically from the existence of orbital angular momentum (OAM) in the Bloch wave functions. Here, we present detailed experimental evidence for this OAM-based origin of the Rashba effect by angle-resolved photoemission (ARPES) and two-photon photoemission (2PPE) experiments for a monolayer AgTe on Ag(111). Using quantitative low-energy electron diffraction (LEED) analysis we determine the structural parameters and the stacking of the honeycomb overlayer with picometer precision. Based on an orbital-symmetry analysis in ARPES and supported by first-principles calculations, we unequivocally relate the presence and absence of Rashba-type spin splittings in different bands of AgTe to the existence of OAM.