Pressure dependence of the metal-insulator transition in κ-(BEDT-TTF)2Hg(SCN)2Cl: optical and transport studies. (12th December 2016)

• Record Type: Journal Article
• Authors: Löhle, A; Rose, E; Singh, S; Beyer, R; Tafra, E; Ivek, T; Zhilyaeva, E I; Lyubovskaya, R N; Dressel, M
• Is Part Of: Journal of physics. Volume 29:Number 5(2017)
• Publication Date: 2016-12-12
• Subjects: charge order -- organic conductors -- correlated electron systems -- hydrostatic pressure -- metal-insulator transition; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/29/5/055601
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The two-dimensional organic conductor κ -(BEDT-TTF)2 -Hg(SCN)2 Cl exhibits a pronounced metal-insulator transition at T C O = 30 K. From the splitting of the molecular vibrations, the phase transition can be unambiguously assigned to charge-ordering with 2 δ ρ = 0.2 e . We have investigated the pressure evolution of this behavior by temperature-dependent electrical transport measurements and optical investigations applying hydrostatic pressure up to 12 kbar. The data reveal a mean-field like down-shift of T C O ( p ) with a critical pressure of p c = 0.7 ± 0.1 kbar and a metallic state above the suppression of the charge-ordered state; no traces of superconductivity could be identified down to T = 1.5 K. As the charge order δ ρ sets in abruptly with decreasing temperature, its size remains unaffected by pressure. However, the fraction of charge imbalanced molecules decreases until it is completely absent above 1.6 kbar.