Negative Compressibility of Single Selenium Chain Confined in Zeolite Pore

TL;DR

This paper demonstrates negative compressibility in a single selenium chain confined in a zeolite pore, combining experimental Raman and absorption data with ab initio calculations to reveal pressure-induced structural and electronic transitions.

Contribution

It provides the first evidence of negative compressibility in a one-dimensional nanostructure through combined experimental and theoretical analysis.

Findings

Band gap reduction under high pressure

Elongation of Se chains under compression

Softening of phonons observed experimentally

Abstract

Pressure induced structural and electronic transitions of Se helical chains confined inside nano-channels are studied. Raman scattering and optical absorption experiments show strong evidence of band gap reduction under high pressure. Ab initio calculations reveal that under hydrostatic compression, the Se chains should elongate and the change in morphology leads to a softening of phonons and narrowing of band gaps, and these signatures are observed in experiments. Our investigation demonstrates a negative compressibility in one dimension.