Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 1: Focus Session: Frustration in Mott Insulators and Mott Criticality
TT 1.5: Hauptvortrag
Montag, 20. März 2017, 11:45–12:15, HSZ 03
The Widom Line in Pristine Mott Insulators: Dynamical Properties of Quantum Spin Liquids — •Andrej Pustogow1, Simone Fratini2, Tsung-Han Lee3, Vladimir Dobrosavljevic3, and Martin Dressel1 — 11. Physikalisches Institut, Universität Stuttgart — 2Institut Néel - CNRS and Université Grenoble Alpes, France — 3Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, USA
In Mott insulators strong electronic interactions prevent the metallic state. As a paradigm of correlated electron systems, the Mott insulating state is under scrutiny theoretically for more than half a century. Still, the low-temperature behavior evaded experimental exploration because it is typically concealed by an antiferromagnetic phase. In quantum spin liquids, however, no magnetic order is reached, offering the unique possibility to elucidate the pristine Mott state. Here we explore the electrodynamic response of three organic quantum spin liquids with different degrees of effective correlation and frustration. The low-frequency behavior strongly depends on the position in the temperature-pressure phase diagram. In particular in the vicinity of the quantum critical point, metallic fluctuations can be identified at low temperatures. Combining our optical data with pressure-dependent transport studies and theoretical calculations, we can construct a universal phase diagram of the correlation-controlled Mott insulator.
This work was done in collaboration with M. Bories, E. Zhukova, B. Gorshunov, M. Pinteric, S. Tomic, J. Schlueter, A. Löhle, R. Hübner, T. Hiramatsu, Y. Yoshida, G. Saito and R. Kato.