Odd-parity superconductivity by competing spin-orbit coupling and orbital effect in artificial heterostructures

Watanabe, Tatsuya; Yoshida, Tomohiro; Yanase, Youichi

doi:10.1103/physrevb.92.174502

Cited by 22 publications

(28 citation statements)

References 70 publications

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“…sgn (∆ out ) = −sgn (∆ in ). This kind of sign change can be understood by analogy to layered superconductors, where non-centrosymmetricity can induce Rashba SOC with signs that alternate between layers, driving a similar sign change of the order parameter [107][108][109]. While our model does not explicitly contain a Rashba-like term, spin-orbit physics is present in the form of DM and Γ interactions.…”

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confidence: 99%

Topological Magnon Bands and Unconventional Superconductivity in Pyrochlore Iridate Thin Films

Laurell

Fiete

2017

Phys. Rev. Lett.

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We theoretically study the magnetic properties of pyrochlore iridate bilayer and trilayer thin films grown along the [111] direction using a strong coupling approach. We find the ground state magnetic configurations on a mean field level and carry out a spin-wave analysis about them. In the trilayer case the ground state is found to be the all-in/all-out (AIAO) state, whereas the bilayer has a deformed AIAO state. For all parameters of the spin-orbit coupled Hamiltonian we study, the lowest magnon band in the trilayer case has a non-zero Chern number. In the bilayer case we also find a parameter range with non-zero Chern numbers. We calculate the magnon Hall response for both geometries, finding a striking sign change as function of temperature. Using a slave-boson mean-field theory we study the doping of the trilayer system and discover an unconventional timereversal symmetry broken d +id superconducting state. Our study complements prior work in the weak coupling limit and suggests that the [111] grown thin film pyrochlore iridates are a promising candidate for topological properties and unconventional orders. 75.30.Ds,71.27.+a Introduction -One of the main focal points of quantum materials research is topological states of matter, where the essential physics is generally due to spin-orbit coupling (SOC) [1][2][3][4]. Another is correlated electron systems, in which electron-electron interactions dominate, leading to interaction-driven insulators, magnetism, and unconventional superconductivity [5]. Even more possibilities open up when both SOC and electron-electron interactions are present, such as fractionalized topological insulators (TI) [6][7][8][9][10][11][12][13][14][15][16][17], interaction-induced TI [18][19][20][21][22][23][24], and unconventional magnetic states [25][26][27]. A promising place to look for both types of physics is in 5d transition-metal oxides, which tend to have comparable electron-electron interaction and SOC strengths [28][29][30].

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confidence: 99%

Topological Magnon Bands and Unconventional Superconductivity in Pyrochlore Iridate Thin Films

Laurell

Fiete

2017

Phys. Rev. Lett.

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“…The concept of PDW state was introduced for spatially inhomogeneous superconducting states in the atomic length scale which is much shorter than the coherence length 86 . In the subsequent works [58][59][60][61][62][63][64] , however, the sign changing order parameter between sublattices has also been classified into the PDW state. In the latter case, the translation symmetry is not broken (q = 0).…”

Section: B Mean Field Theorymentioning

confidence: 99%

“…Such a superconducting state has been identified as a pair-density-wave (PDW) state. Interestingly, multilayer odd-parity superconductivity is classified into the topological crystalline superconductivity [62][63][64] , and zigzag chains are identified as Z 2 topological superconductors 61 . In this paper we propose the material realization of analogous odd-parity superconductivity in bilayer TMDCs.…”

Section: Introductionmentioning

confidence: 99%

Odd-parity superconductivity in bilayer transition metal dichalcogenides

Nakamura

Yanase

2017

Phys. Rev. B

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Spin-orbit coupling in transition metal dichalcogenides (TMDCs) causes spin-valley locking giving rise to unconventional optical, transport, and superconducting properties. In this paper, we propose exotic superconductivity in bilayer group-IV TMDCs by symmetry control. The sublatticedependent "hidden" spin-orbit coupling arising from local inversion symmetry breaking in the crystal structure may stabilize the odd-parity superconductivity by purely s-wave local pairing interaction. The stability of the odd-parity superconducting state depends on the bilayer stacking. The 2H b stacking in MoX2 and WX2 (X =S, Se) favors the odd-parity superconductivity due to interlayer quantum interference. On the other hand, the odd-parity superconductivity is suppressed by the 2Ha stacking of NbSe2. Calculating the phase diagram of the tight-binding model derived from first principles band calculations, we conclude that the intercalated bilayer MoS2 and WS2 are candidates for a new class of odd-parity superconductors by spin-orbit coupling.

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“…This lack of local mirror symmetry leads to Rashba-type spin-orbit coupling which induces parity-mixing for the Cooper paring states and at the same time reduces the effect of paramagnetic limiting for fields perpendicular to the layers 13 . Soon it was recognized that this structure could give rise to various intriguing properties in a magnetic field, such as a complex stripes phase related to the FFLO state, crystalline topological superconductivity and pair density wave phases among other features 12,[14][15][16][17][18][19][20] . The important ingredient for this is local non-centrosymmetricity and a large Maki parameter.…”

Section: Introductionmentioning

confidence: 99%

Orbitally limited pair-density-wave phase of multilayer superconductors

2018

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We investigate the magnetic field dependence of an ideal superconducting vortex lattice in the parity-mixed pair-density wave phase of multilayer superconductors within a circular cell Ginzburg-Landau approach. In multilayer systems, due to local inversion symmetry breaking, a Rashba spinorbit coupling is induced at the outer layers. This combined with a perpendicular paramagnetic (Pauli) limiting magnetic field stabilizes a staggered layer dependent pair-density wave phase in the superconducting singlet channel. The high-field pair-density wave phase is separated from the low-field BCS phase by a first-order phase transition. The motivating guiding question in this paper is: what is the minimal necessary Maki parameter αM for the appearance of the pair-density wave phase of a superconducting trilayer system? To address this problem we generalize the circular cell method for the regular flux-line lattice of a type-II superconductor to include paramagnetic depairing effects. Then, we apply the model to the trilayer system, where each of the layers are characterized by Ginzburg-Landau parameter κ0, and a Maki parameter αM . We find that when the spin-orbit Rashba interaction compares to the superconducting condensation energy, the orbitally limited pair-density wave phase stabilizes for Maki parameters αM > 10.

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Odd-parity superconductivity by competing spin-orbit coupling and orbital effect in artificial heterostructures

Cited by 22 publications

References 70 publications

Topological Magnon Bands and Unconventional Superconductivity in Pyrochlore Iridate Thin Films

Topological Magnon Bands and Unconventional Superconductivity in Pyrochlore Iridate Thin Films

Odd-parity superconductivity in bilayer transition metal dichalcogenides

Orbitally limited pair-density-wave phase of multilayer superconductors

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