Superconductivity in three-dimensional spin-orbit coupled semimetals

Journal Article · Thu Dec 28 04:00:00 EST 2017 · Physical Review. B

DOI:https://doi.org/10.1103/physrevb.96.214514· OSTI ID:1505765

Savary, Lucile ^[1]; Ruhman, Jonathan ^[2]; Venderbos, Jörn W. F. ^[2]; Fu, Liang ^[2]; Lee, Patrick A. ^[2]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Université de Lyon (France); MIT
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Here, motivated by the experimental detection of superconductivity in the low-carrier density half-Heusler compound YPtBi, we study the pairing instabilities of three-dimensional strongly spin-orbit coupled semimetals with a quadratic band touching point. In these semimetals the electronic structure at the Fermi energy is described by spin j = 3/2 quasiparticles, which are fundamentally different from those in ordinary metals with spin j = 1/2. For both local and nonlocal pairing channels in j = 3/2 materials we develop a general approach to analyzing pairing instabilities, thereby providing the computational tools needed to investigate the physics of these systems beyond phenomenological considerations. Furthermore, applying our method to a generic density-density interaction, we establish that: (i) The pairing strengths in the different symmetry channels uniquely encode the j = 3/2 nature of the Fermi surface band structure—a manifestation of the fundamental difference with ordinary metals. (ii) The leading odd-parity pairing instabilities are different for electron doping and hole doping. Finally, we argue that polar phonons, i.e., Coulomb interactions mediated by the long-ranged electric polarization of the optical phonon modes, provide a coupling strength large enough to account for a Kelvin-range transition temperature in the s-wave channel, and are likely to play an important role in the overall attraction in non- s -wave channels. Furthermore, the explicit calculation of the coupling strengths allows us to conclude that the two largest non- s-wave contributions occur in nonlocal channels, in contrast with what has been commonly assumed.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
• Grant/Contract Number: FG02-03ER46076; SC0010526
• OSTI ID: 1505765
• Alternate ID(s): OSTI ID: 1416451
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 21 Vol. 96; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY