Pairing Mechanism of Unconventional Superconductivity in Doped Kane–Mele Model

Fukaya, Yuri; Yada, Keiji; Hattori, Ayami; Tanaka, Yukio

doi:10.7566/jpsj.85.104704

Cited by 10 publications

(6 citation statements)

References 78 publications

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“…In accordance with the mechanism studied here for the spinless case, proximity to a CDW instability on the triangular [45][46][47] , honeycomb 31 , and also the square 48 lattice supports fwave solutions. More recently, spin-orbit coupling 49,50 has been suggested to favor SC solutions with f -wave symmetry.…”

Section: Superconducting F -Wave Instabilitymentioning

confidence: 99%

Bond-ordered states and f -wave pairing of spinless fermions on the honeycomb lattice

Heßelmann

Scherer

et al. 2018

Phys. Rev. B

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Spinless fermions on the honeycomb lattice with repulsive nearest-neighbor interactions are known to harbour a quantum critical point at half-filling, with critical behavior in the Gross-Neveu (chiral Ising) universality class. The critical interaction strength separates a weak-coupling semimetallic regime from a commensurate charge-density-wave phase. The phase diagram of this basic model of correlated fermions on the honeycomb lattice beyond half-filling is, however, less well established. Here, we perform an analysis of its many-body instabilities using the functional renormalization group method with a basic Fermi surface patching scheme, which allows us to treat instabilities in competing channels on equal footing also away from half-filling. Between half-filling and the Van Hove filling, the free Fermi surface is holelike and we again find a charge-density wave instability to be dominant at large interactions. Moreover, its characteristics are those of the half-filled case. Directly at the Van Hove filling, the nesting property of the free Fermi surface stabilizes a dimerized bond-order phase. At lower filling, the free Fermi surface becomes electronlike and a superconducting instability with f -wave symmetry is found to emerge from the interplay of intra-unit-cell repulsion and collective fluctuations in the proximity to the charge-density wave instability. We estimate the extent of the various phases and extract the corresponding order parameters from the effective low-energy Hamiltonians.arXiv:1805.02490v2 [cond-mat.str-el]

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Section: Superconducting F -Wave Instabilitymentioning

confidence: 99%

Bond-ordered states and f -wave pairing of spinless fermions on the honeycomb lattice

Heßelmann

Scherer

et al. 2018

Phys. Rev. B

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“…Here we study the case where spin rotational invariance is broken in the paramagnetic phase, due to SOC. We now apply this formalism to an extended Kane-Mele Hubbard model on a bipartite honeycomb lattice [21][22][23][24]. This is a toy model for a TMD.…”

Section: Methodsmentioning

confidence: 99%

“…To study this phenomenon, we compute spin fluctuations using the random phase approximation (RPA) for two types of Hamiltonians. First, we consider the Kane-Mele-Hubbard model [21][22][23][24] with a sublattice potential term that breaks inversion symmetry, leading to spin-valley coupled bands. Second, we consider a multiorbital effective Hamiltonian (tight-binding like) obtained from DFT calculations describing a monolayer of 2H-NbSe 2 .…”

Section: Introductionmentioning

confidence: 99%

Ising and XY paramagnons in two-dimensional 2H−NbSe2

Costa

Fernández-Rossier

2022

Phys. Rev. B

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Paramagnons are the collective modes that govern the spin response of nearly magnetic conductors. In some cases they mediate electron pairing leading to superconductivity. This scenario may occur in 2H-NbSe 2 monolayers, that feature spin-valley coupling on account of spin-orbit interactions and their lack of inversion symmetry. Here we explore spin anisotropy of paramagnons both for noncentrosymmetric Kane-Mele-Hubbard models for 2H-NbSe 2 monolayers described with a DFT-derived tight-binding model. In the infinite wavelength limit we find spatially uniform paramagnons with energies around 1 meV that feature a colossal off-plane uniaxial magnetic anisotropy, with quenched transversal spin response. At finite wave vectors, longitudinal and transverse channels reverse roles: XY fluctuations dominate within a significant portion of the Brillouin zone. Our results show that 2H-NbSe 2 is close to a Coulomb-driven in-plane (XY) spin density wave instability.

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“…On the other hand, a disconnected form of the FS is favorable for the odd-parity pairing since generation of gap nodes is avoidable [21,22]. Stabilization of odd-parity spin-triplet pairing states has been theoretically proposed in a variety of systems with disconnected FSs, e.g., (TMTSF) 2 X (X = PF 6 ,ClO 4 ) [21,[23][24][25][26], Na x CoO 2 • yH 2 O [27][28][29][30][31][32][33][34][35], SrPtAs [36,37], and doped Kane-Mele model [38].…”

Section: Introductionmentioning

confidence: 99%

Multiple odd-parity superconducting phases in bilayer transition metal dichalcogenides

Kanasugi,

Yanase

2020

Preprint

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We study unconventional superconductivity in a two-dimensional locally noncentrosymmetric triangular lattice. The model is relevant to bilayer transition metal dichalcogenides with 2H b stacking structure, for example. The superconducting instability is analyzed by solving the linearized Eliashberg equation within the random phase approximation. We show that ferromagnetic fluctuations are dominant owing to the existence of disconnected Fermi pockets near van Hove singularity, and hence odd-parity spin-triplet superconductivity is favored. In the absence of the spin-orbit coupling, we find that odd-parity f -wave superconducting state is stabilized in a wide range of carrier density and interlayer coupling. Furthermore, we investigate impacts of the layer-dependent staggered Rashba and Zeeman spin-orbit coupling on the superconductivity. Multiple odd-parity superconducting phase diagrams are obtained as a function of the spin-orbit coupling and Coulomb interaction. Especially, a topological chiral p-wave pairing state is stabilized in the presence of a moderate Zeeman spin-orbit coupling. Our results shed light on a possibility of odd-parity superconductivity in various ferromagnetic van der Waals materials.

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Pairing Mechanism of Unconventional Superconductivity in Doped Kane–Mele Model

Cited by 10 publications

References 78 publications

Bond-ordered states and f -wave pairing of spinless fermions on the honeycomb lattice

Bond-ordered states and f -wave pairing of spinless fermions on the honeycomb lattice

Ising and XY paramagnons in two-dimensional 2H−NbSe2

Multiple odd-parity superconducting phases in bilayer transition metal dichalcogenides

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