Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session C30: Superconductivity: Less Common Materials
2:30 PM–5:06 PM,
Monday, March 5, 2018
LACC Room: 406B
Sponsoring Unit: DCMP
Chair: Robert Cava, Princeton University
Abstract: C30.00007 : Possible high-Tc superconductivity in Ruddlesden-Popper compounds: Incipient narrow bands originating from “hidden ladders”
3:42 PM–3:54 PM
(University of Tokyo)
It has been suggested that superconductivity should be strongly enhanced in systems with coexisting wide and narrow bands, as in the two-leg Hubbard ladder with the second-neighbor hopping when the Fermi level EF is put near the narrow band edge. As a way to realize this situation in actual materials, we introduce a concept of a “hidden ladder” electronic structure in the bilayer Ruddlesden-Popper compounds. When EF crosses the bands with t2g orbital character, an electron in the dxz/yz orbital selectively hops in the x/y direction as well as in the z direction normal to the bilayer. This means that the dxz/yz orbital form a ladder with x/y and z directions being the leg and rung directions, respectively. We propose that Sr3Mo2O7 and Sr3Cr2O7 are candidates for the hidden ladder materials where EF sits right in the vicinity of the narrow-band edge. Based on this electronic structure, we discuss possible occurrence of high-Tc superconductivity in these materials originating from the large number of interband pair-scattering channels between the wide and the “incipient” narrow bands.
References:  K. Kuroki, et al., Phys. Rev B, 72, 212509 (2005).  D. Ogura, et al., arXiv: 1706.01711 (2017).
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