Superconductivity in three-dimensional spin-orbit coupled semimetals
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Université de Lyon (France)
- 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, Vol. 96, Issue 21; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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