Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 46: Low-Dimensional Systems: Molecular Conductors
TT 46.6: Vortrag
Dienstag, 1. April 2014, 15:15–15:30, HSZ 204
Studying the Mott criticality via thermal expansion under 4He-gas pressure — •Rudra Sekhar Manna1, Elena Gati1, Ulrich Tutsch1, Takahiko Sasaki2, and Michael Lang1 — 1Physics Institute, Goethe University Frankfurt (M), SFB/TR 49, D-60438 Frankfurt (M), Germany — 2Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
Quasi-2D organic charge-transfer salts κ-(ET)2X show a variety of ground state properties accessible upon either changing the anion X or by applying hydrostatic pressure. The T-P phase diagram includes a first-order Mott transition line which terminates at a second-order critical end point. Interestingly, deuterated κ-(d8-ET)2Cu[N(CN)2]Br (κ-d8 in short) lies on the verge of the Mott transition line at ambient pressure. Thus, for this material temperature sweeps are sufficient to experimentally access the critical end point and thereby to study the controversy surrounding the Mott criticality. Recent scaling theory [1] applied to previous thermal expansion data on κ-d8 crystals [2] speaks in favor of a 2D Ising universality class. Here we present thermal expansion measurements performed under 4He-gas pressure [3] on κ-d8 crystals along the in-plane a-axis. The aim of this work is to pressure-tune the system in the vicinity of the Mott critical end point and to compare the results with theoretical predictions [1, 4].
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