Temperature- and pressure-dependent metallic states in (BEDT-TTF)8[Hg4Br12(C6H5Br)2]

TL;DR

This study investigates temperature- and pressure-induced electronic phase transitions in a BEDT-TTF-based organic conductor, revealing structural influences and Fermi liquid behavior through experimental and theoretical analysis.

Contribution

It provides new insights into the mechanisms of metal-insulator and insulator-metal transitions driven by temperature and pressure in this material.

Findings

Temperature decreases cause a gap opening linked to structural changes.

Pressure influences SdH oscillations, indicating many-body interactions.

All data are consistent with a Fermi liquid description.

Abstract

Temperature-driven metal-insulator and pressure-driven insulator-metal transitions observed in(BEDT-TTF)8[Hg4X12(C6H5Y)2]] with X = Y = Br are studied through band structure calculations based on X-ray crystal structure determination and Shubnikov-de Haas (SdH) oscillations spectra, respectively. In connection with chemical pressure effect, the transition, which is not observed for X = Cl, is due to gap opening linked to structural changes as the temperature decreases. Even though many body interactions can be inferred from the pressure dependence of the SdH oscillations spectra, all the data can be described within a Fermi liquid picture.