# $d_{xz/yz}$ Orbital Subband Structures and Chiral Orbital Angular Momentum in the (001) Surface States of SrTiO$_3$

## TL;DR

This study uses ARPES to explore the subband structures and chiral orbital angular momentum in the surface states of SrTiO$_3$(001), revealing new subbands and suggesting a chiral OAM structure that could explain Rashba-like splitting.

## Contribution

It reports the discovery of additional $d_{xz/yz}$ subbands and evidence of chiral OAM in SrTiO$_3$ surface states, advancing understanding of their electronic structure.

## Key findings

- New $d_{xz/yz}$ subbands identified with specific Fermi wave vectors.
- Evidence of chiral orbital angular momentum in surface states.
- Insights into the origin of Rashba-like surface band splitting.

## Abstract

We have performed angle resolved photoemission spectroscopy (ARPES) experiments on the surface states of SrTiO$_3$(001) using linearly and circularly polarized light to investigate the subband structures of out-of-plane $d_{xz/yz}$ orbitals and chiral orbital angular momentum (OAM). The data taken in the first Brillouin zone reveal new subbands for $d_{xz/yz}$ orbitals with Fermi wave vectors of 0.25 and 0.45 $\mathrm{\AA}^{-1}$ in addition to the previously reported ones. As a result, there are at least two subbands for all the Ti 3d t$_{2g}$ orbitals. Our circular dichroism ARPES data is suggestive of a chiral OAM structure in the surface states and may provide clues to the origin of the linear Rashba-like surface band splitting.