CDW signatures in the electronic structure of LaSb2 at 13 K and metal-insulator transition

TL;DR

This study combines ARPES measurements and DFT calculations to investigate CDW signatures in LaSb2 at 13 K and 200 K, revealing temperature-dependent electronic structure changes and potential structural distortions linked to CDW formation.

Contribution

It provides new insights into the temperature-dependent electronic structure and CDW manifestations in LaSb2 through combined experimental and theoretical analysis.

Findings

ARPES shows metallic behavior at 200 K and semiconducting at 13 K.

Band folding and nesting vector identified at q = 0.25 Å⁻¹.

Evidence of in-plane distortion affecting the entire unit cell.

Abstract

Light rare-earth antimonide LaSb2 is a material susceptible to nesting and exhibits a Charge Density Wave (CDW) at 355 K as well as superconductivity below 1.2 K. In the seek for additional CDW transitions, we have studied the temperature-dependent of LaSb2 at 200 and 13 K and infer CDW manifestations by combining angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations. ARPES measurements at 200 K show a metallic system while it appears to be semiconducting at 13 K, at odds with existing resistivity measurements. At 13 K, ARPES shows the band folding of the inner Fermi surface pockets, with considerable spectral weight on the folded band. We find a nesting vector at q = 0.25$\pm$0.02 {\AA} -1. In addition, we observe Umklapps of other bands due to the onset of the new periodicity, together with a semiconducting behavior in the whole reciprocal space. Calculations demonstrate that the folded band is associated with the La-Sb layer and that in-plane distortion is the most probable structural modification in the system, probably affecting the whole unit cell.