Infrared spectroscopy under multi-extreme conditions: Direct observation of pseudo gap formation and collapse in CeSb

TL;DR

This study uses infrared spectroscopy to observe the formation and collapse of a pseudo gap in CeSb under combined extreme conditions of low temperature, high pressure, and high magnetic field, revealing phase-dependent electronic structure changes.

Contribution

First direct optical observation of pseudo gap formation and collapse in CeSb under multi-extreme conditions, linking magnetic phases to electronic structure changes.

Findings

Pseudo gap forms at 4 GPa and 35-50 K in CeSb.

Pseudo gap spectrum changes with magnetic field and temperature.

Pseudo gap collapses during magnetic phase transitions.

Abstract

Infrared reflectivity measurements of CeSb under multi-extreme conditions (low temperatures, high pressures and high magnetic fields) were performed. A pseudo gap structure, which originates from the magnetic band folding effect, responsible for the large enhancement in the electrical resistivity in the single-layered antiferromagnetic structure (AF-1 phase) was found at a pressure of 4 GPa and at temperatures of 35 - 50 K. The optical spectrum of the pseudo gap changes to that of a metallic structure with increasing magnetic field strength and increasing temperature. This change is the result of the magnetic phase transition from the AF-1 phase to other phases as a function of the magnetic field strength and temperature. This result is the first optical observation of the formation and collapse of a pseudo gap under multi-extreme conditions.