University of Connecticut

Events Calendar

Cancelled: Special Condensed Matter Physics Seminar

Thursday, November 21, 2019
2:00pm – 3:00pm

Storrs Campus
GS 119

Prof. Jie Wu, Westlake University, China

Electronic nematicity in unconventional superconductors

The mechanism of high temperature superconductivity is a long-standing mystery in condensed matter physics. Despite of the intensive efforts devoted to this topic since its discovery in 1987, the nature of the superconducting state and the normal state remains ambiguous. Starting from an unexpected observation that the voltage transverse to the current direction is not zero in high temperature superconductors (HTS), I will present our investigations for the underlying mechanism, which at the end leads to the picture of the spontaneous breaking of the rotational symmetry in the normal state of HTS. Such a peculiar state is named as the electronic nematic state, implying its origin is the electron-electron correlation and, more importantly, the motion of electrons is anisotropic in the Cu-O plane. This challenges the basics of the Fermi liquid theory that the electrons’ motion is isotropic as the word “liquid” implies. By studying how the nematicity evolves with the temperature and the chemical doping, our experiments reach the conclusion that the high temperature superconductivity in fact emerges out of the electronic nematic state. Other unconventional superconductors, such as ruthenate and Fe-based superconductors, show very similar behavior, indicating the electronic nematicity may be deeply correlated with unconventional superconductivity.

I will also briefly discuss our findings of the dependence of the superconducting temperature on the superfluid density, the abnormal independence of the interface superconductivity on the chemical doping, and the charge cluster glass state in the vicinity of the superconductor-insulator transition. All these findings constitute a vague but coherent picture of HTS.

References:

1. J. Wu, A. T. Bollinger, X. He and I. Božović, “Spontaneous breaking of rotational symmetry in copper oxide superconductors”, Nature 547, 432-435 (2017).

2. I. Božović, X. He, J. Wu and A. T. Bollinger, “Dependence of the critical temperature in overdoped copper oxides on superfluid density”, Nature 536, 309-311 (2016).

3. J. Wu, A. T. Bollinger, J. Sun and I. Božović, “Hall effect in quantum critical charge cluster glass”, Proc. Natl. Acad. Sci. USA 113, 4284-4289 (2016).

4. J. Wu, O. Pelleg, G. Logvenov, A. T. Bollinger, J. Sun, G. S. Boebinger, M. Vanević, Z. R adović and I. Božović, “Anomalous independence of interface superconductivity from carrier density”, Nature Materials 12, 877-881 (2013).

Contact:

Prof. I. Sochnikov

Physics Department (primary), UConn Master Calendar

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