TY - JOUR
T1 - Weak-pairing higher order topological superconductors
AU - Wang, Yuxuan
AU - Lin, Mao
AU - Hughes, Taylor L.
N1 - Funding Information:
We thank W. A. Benalcazar and Zhong Wang for discussions. Y.W. acknowldeges support from the Gordon and Betty Moore Foundations EPiQS Initiative through Grant No. GBMF4305. M.L. thanks NSF Emerging Frontiers in Research and Innovation NewLAW program Grant No. EFMA-1641084 and NSF CAREER Grant No. DMR-1351895 for support. T.L.H. was supported by the ONR YIP Award No. N00014-15-1-2383.
Publisher Copyright:
© 2018 American Physical Society.
PY - 2018/10/29
Y1 - 2018/10/29
N2 - Conventional topological superconductors are fully gapped in the bulk but host gapless Majorana modes on their boundaries. We instead focus on a new class of superconductors, second-order topological superconductors, that have gapped, topological surfaces and gapless Majorana modes instead on lower-dimensional boundaries, i.e., corners of a two-dimensional system or hinges for a three-dimensional system. Here, we propose two general scenarios in which second-order topological superconductivity can be realized spontaneously with weak-pairing instabilities. First, we show that (px+ipy)-wave pairing in a (doped) Dirac semimetal in two dimensions with four mirror-symmetric Dirac nodes realizes second-order topological superconductivity. Second, we show that p+id pairing on an ordinary spin-degenerate Fermi surface realizes second-order topological superconductivity as well. In the latter case, we find that the topological invariants describing the system can be written using simple formulas involving only the low-energy properties of the Fermi surfaces and superconducting pairing. In both cases, we show that these exotic superconducting states can be intrinsically realized in a metallic system with electronic interactions. For the latter case, we also show it can be induced by proximity effect in a heterostructure of cuprate and topological superconductors.
AB - Conventional topological superconductors are fully gapped in the bulk but host gapless Majorana modes on their boundaries. We instead focus on a new class of superconductors, second-order topological superconductors, that have gapped, topological surfaces and gapless Majorana modes instead on lower-dimensional boundaries, i.e., corners of a two-dimensional system or hinges for a three-dimensional system. Here, we propose two general scenarios in which second-order topological superconductivity can be realized spontaneously with weak-pairing instabilities. First, we show that (px+ipy)-wave pairing in a (doped) Dirac semimetal in two dimensions with four mirror-symmetric Dirac nodes realizes second-order topological superconductivity. Second, we show that p+id pairing on an ordinary spin-degenerate Fermi surface realizes second-order topological superconductivity as well. In the latter case, we find that the topological invariants describing the system can be written using simple formulas involving only the low-energy properties of the Fermi surfaces and superconducting pairing. In both cases, we show that these exotic superconducting states can be intrinsically realized in a metallic system with electronic interactions. For the latter case, we also show it can be induced by proximity effect in a heterostructure of cuprate and topological superconductors.
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U2 - 10.1103/PhysRevB.98.165144
DO - 10.1103/PhysRevB.98.165144
M3 - Article
AN - SCOPUS:85056264133
VL - 98
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 16
M1 - 165144
ER -