Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 1: Focus Session: Frustration in Mott Insulators and Mott Criticality

TT 1.3: Hauptvortrag

Montag, 20. März 2017, 10:30–11:00, HSZ 03

The Fate of Spinons in Quantum Critical Mott Systems — •Vladimir Dobrosavljevic — Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA

Recent theoretical and experimental work found evidence of quantum critical scaling behavior around bandwidth-driven Mott transitions in several organic systems of the kappa-family. These experimental results show remarkably universal scaling features, which appear largely identical both in materials displaying long-range antiferromagnetic order on the insulating side, and those showing spin liquid signatures at the lowest temperatures. To provide insight in the role of spin correlations in the critical regime, we blend dynamical mean-field theory (which provided remarkably good description of the high temperature regime), and the RVB-spinon mean-field theory, which describes the spin liquid excitations on the insulating side. Our results indicate that spinon excitations suffer very strong inelastic scattering from dynamical charge fluctuations as soon as the Mott gap closes. We conclude that while spinon excitations dominate the low-temperature insulating regime, they prove largely irrelevant in the entire high-temperature quantum critical regime, in agreement with all available experimental data.