University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Thursday, April 2nd 2015
1:25 pm:
Condensed Matter Seminar in 210 Physics
Speaker: James Analytis, UC Berkeley
Subject: Magnetoresistance near a quantum critical point

The physics of quantum critical phase transitions connects to some of the most difficult problems in condensed matter physics, including metal-insulator transitions, frustrated magnetism and high temperature superconductivity.
Near a quantum critical point(QCP)a new kind of metal emerges, whose thermodynamic and transport properties do not fit into the unified phenomenology with which we understand conventional metals - the
Landau Fermi liquid(FL)theory - characterized by a low temperature limiting T-linear specific heat and a T^2 resistivity.Studying the evolution of the T­ dependence of these observables as a function of a control parameter leads to the identification both of the presence and the nature
of the quantum phase transition in candidate systems. In this study we measure the transport properties of BaFe2(As1-xPx)2,at T by suppressing superconductivity with high magnetic fields. We find an anomalous magnetic field dependence that suggests that not only does magnetic field directly affect the scattering rate (which is unusual for metals), but it does so in a way that is identical to temperature. We suggest that there is a universal phenomenology of scattering near a quantum critical point.

Faculty Host: Andrey Chubukov

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