Mukul Laad

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Unconventional Superconductivity (USC) in layered Sr$_{2}$RuO$_{4}$
is of long-standing interest because it is long thought to be a
superconducting analogue of $^{3}He$. However, resurgence of recent
data points toward a much more involved pairing symmetry, where the
interplay between multi-band character, sizable multi-band
electronic correlations and strong spin-orbit coupling conspires to
select an apparently rather unusual, hitherto unknown, USC pair
symmetry. This mandates detailed revisiting of the normal state
and, in particular, of the $T$-dependent incoherence-coherence
crossover. Here, using a modern first-principles correlated view,
we study this issue in the real structure of Sr$_{2}$RuO$_{4}$ in
detail and present a unified and quantitative description of a range
of unusual physical responses in the normal state across the
crossover. Armed with these strengths, we propose that a new and
important element, that of dominant (quasi-one-dimensional $xz,yz$)
interband charge fluctuations in a ``Hund'' metal, may be a primary
pair glue for USC in this system. We will emphasize internal
consistency of our proposed scenario vis-a-vis a wide range of
constraints imposed by extant data.

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University of Chennai
Seminar Room Kernphysik
Contact: Simon Trebst