Who
Jonathan Ruhman, Bar-Ilan University
Abstract
According to the standard theory of superconductivity electronic pairing results form the exchange of longitudinal phonons. This picture relies on two essential conditions: (1) A large separation of scales between the Fermi energy and the Debye frequency. (2) A large effective coupling between electrons and phonons.
Consequently, we do not anticipate doped materials, where both of these conditions are typically not fulfilled, to exhibit superconductivity. Nonetheless, it is ubiquitous in doped materials, including SrTiO3, Bi2Se3, PbTe, SnTe, Bi, YPtBi, Cd3As2 and more...
In this talk I will describe the main challenges in our microscopic understanding of pairing. I will discuss possible paring mechanisms including the exchange of polar modes and fluctuations near a ferroelectric quantum critical point. I will then conclude by discussing the importance of spin-orbit coupling and disorder. The latter is related to experimental observations consistent with robust topological pairing states. Based on the Abrikosov-Gor'kov theory, I will argue that unconventional pairing is much more prone to disorder than what was previously understood.
Consequently, we do not anticipate doped materials, where both of these conditions are typically not fulfilled, to exhibit superconductivity. Nonetheless, it is ubiquitous in doped materials, including SrTiO3, Bi2Se3, PbTe, SnTe, Bi, YPtBi, Cd3As2 and more...
In this talk I will describe the main challenges in our microscopic understanding of pairing. I will discuss possible paring mechanisms including the exchange of polar modes and fluctuations near a ferroelectric quantum critical point. I will then conclude by discussing the importance of spin-orbit coupling and disorder. The latter is related to experimental observations consistent with robust topological pairing states. Based on the Abrikosov-Gor'kov theory, I will argue that unconventional pairing is much more prone to disorder than what was previously understood.
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