On February 21st, 2014, at 14:00, in the library of the Institute of Physics Belgrade, SCL's Darko Tanaskovic will present a seminar talk entitled:

"Quantum critical transport near the Mott metal-insulator transition"

Abstract: Strong electronic correlations in transition metal oxides and many other compounds, like Mott quasi-twodimensional organic crystals, lead to different ordered phases at low temperatures. Particularly interesting is a possibility to change the zero temperature ground state by tuning an external parameter. An approach to the quantum critical point is often inaccessible not only due to the zero temperature, but also due to various instabilities and ordering in its proximity. The understanding of the phase transition is nevertheless of fundamental importance since the existence of the quantum critical point often determines transport and thermodynamic properties in a broad temperature range, with a characteristic scaling of physical quantities and universality.

In the talk, a scaling analysis of various transport regimes on the phase diagram of the frustrated Hubbard model will be presented. Special focus is in the incoherent transport at the “high-temperature” crossover region between a metal and an insulator. Our analysis has revealed the scaling of the resistivity curves, which is interpreted as an evidence of the existence of a hidden Mott quantum critical point. This behavior, which is surprisingly similar to experimental findings on Si MOSFETs and organic charge-transfer salts, indicates that Mott quantum criticality may be acting as the fundamental mechanism behind the unusual transport phenomena in many systems near the metal-insulator transition.

[1] J. Vučičević, H. Terletska, D. Tanasković, V. Dobrosavljević, Phys. Rev. B 88, 075143 (2013)
[2] H. Terletska, J. Vučičević, D. Tanasković, V. Dobrosavljević, Phys. Rev. Lett. 107, 026401 (2011)
[3] M. M. Radonjić, D. Tanasković, V. Dobrosavljević, K. Haule, and G. Kotliar, Phys. Rev. B 85, 085133 (2012)