X-ray-induced electrical conduction in the insulating phase of thiospinel CuIr2S4

TL;DR

This study demonstrates that x-ray irradiation significantly reduces electrical resistance and induces structural changes in CuIr2S4, revealing the destruction of Ir4+ dimers as a key mechanism in the insulating phase.

Contribution

It provides new insights into how x-ray irradiation affects the structural and electrical properties of CuIr2S4, highlighting the destruction of Ir4+ dimers as a novel mechanism.

Findings

Resistance decreases by over five decades upon x-ray irradiation.

Structural transition from triclinic to tetragonal occurs simultaneously.

Slow relaxation observed in the x-ray-induced conductive state.

Abstract

Effects of x-ray irradiation on the crystal structure and the electrical resistance were examined at low temperatures for the insulating phase of spinel compound CuIr2S4. We found that the resistance decreases by more than five decades by irradiation at 8.5 K. The structural change from triclinic to tetragonal was observed at the same time. The x-ray-induced conductance is deduced to result from the destruction of Ir4+ dimers formed in the insulating phase. Slow relaxation of the resistance in the x-ray-induced state is also reported.