Cubic Reference Lattice of Bismuth Superconductivity Proposed

by Tommy on 4/05/2017

It looks like somebody already beat me to it.

Theory of Ultra Low Tc Superconductivity in Bismuth: Tip of an Iceberg?, G. Baskaran (3 May 2017)

Superconductivity with an ultra low Tc ∼ 0.5 mK was discovered recently in bismuth, a semimetal. To develop a model and scenario for Bi we begin with a cubic reference lattice, close to A7 (dimerized cubic) structure of Bi. Three valence electrons hop among 6px, 6py and 6pz orbitals and form quasi one dimensional chains at half filling}. An interesting interplay follows: i) Mott localization tendency in the chains, ii) metallization by interchain hopping and iii) lattice dimerization by electron-phonon coupling. In our proposal, a potential high Tc superconductivity from RVB mechanism is lost in the game. However some superconducting fluctuations survive. Tiny fermi pockets seen in Bi are viewed as remnant evanescent Bogoliubov quasi particles} in an anomalous normal state. Multi band character admits possibility of PT violating chiral singlet superconductivity}. Bi has a strong spin orbit coupling; Kramers theorem protects our proposal for the bulk by replacing real spin by Kramer pair. Control of chain dimerization might resurrect high Tc superconductivity in Bi, Sb and As.

This far better than I could have done, a serious paper with a unique approach.

The problem is reconciling cubic with the trigonal mess.

This is coming whether you like it or not.

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