Evidence for Gamma_8 Ground-State Symmetry of Cubic YbB12 Probed by Linear Dichroism in Core-Level Photoemission

TL;DR

This study demonstrates the use of linear dichroism in core-level photoemission to determine the Gamma_8 ground-state symmetry of Yb3+ ions in cubic YbB12, combining experimental observations with theoretical simulations.

Contribution

It provides direct experimental evidence and theoretical validation for the Gamma_8 ground-state symmetry in YbB12 using linear dichroism analysis.

Findings

Linear dichroism observed in YbB12 core-level spectra.

Spectral simulations confirm Gamma_8 ground-state symmetry.

Quantitative agreement between experiment and theory.

Abstract

We have successfully observed linear dichroism in angle-resolved Yb3+ 3d5/2 core-level photoemission spectra for YbB12 in cubic symmetry. Its anisotropic 4f charge distribution due to the crystal-field splitting is responsible for the linear dichroism, which has been verified by spectral simulations using ionic calculations with the full multiplet theory for a single-site Yb3+ ion in cubic symmetry. The observed linear dichroism as well as the polarization-dependent spectra in two different photoelectron directions for YbB12 are quantitatively reproduced by theoretical analysis for the Gamma_8 ground state, indicating the Gamma_8 ground-state symmetry for the Yb3+ ions mixed with the Yb2+ state.