Electronic multipoles and multiplet pairs induced by Pomeranchuk and Cooper instabilities of Bogoliubov Fermi surfaces

Tamura, Shun-Ta; Iimura, Shoma; Hoshino, Shintaro

doi:10.1103/physrevb.102.024505

Cited by 25 publications

(29 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, our mean-field calculations show that, when the Bogoliubov Fermi surface carries two topological charges, the superfluid stiffness is always negative in the clean limit because the spectral weight diverges logarithmically as the temperature approaches zero in the superconducting state (because σ(ω) ∝ ω −1 at low frequencies and the spectrum is gapless.). This is consistent with other studies of inversion-breaking instabilities of Bogoliubov Fermi surfaces [45][46][47] from different perspectives. In particular, Ref.…”

Section: Discussionsupporting

confidence: 93%

Many-body selection rule for quasiparticle pair creations in centrosymmetric superconductors

Ahn,

Nagaosa

2021

Preprint

View full text Add to dashboard Cite

When metal becomes superconducting, new optical excitation channels are created by particle-hole mixing. These excitation channels contribute negligibly to optical responses in most superconductors, but they can be relevant in ultra-strong-coupling superconductors that are close to the Bose-Einstein condensate regime. Recently, selection rules for these excitations have been formulated based on single-particle anti-unitary symmetries in the mean-field theory. While being potentially useful for studying optical properties of ultra-strong-coupling superconductors, they had fundamental limitations because significant quantum fluctuations invalidate meanfield approaches. Here, we use many-body states to formulate an optical selection rule that does not rely on the mean-field approximation. In this approach, the physical meaning of the previous selection rules becomes clearer as they are simply recast as the selection rule for many-body inversion eigenstates, not involving antiunitary symmetries. This selection rule applies not only to the Bogoliubov quasiparticles of Fermi liquids but also to non-Fermi-liquid quasiparticles and electrically charged bosonic excitations. We also study the Bogoliubov Fermi surfaces, whose topological stability is closely related to the selection rule. We provide a many-body formulation of their topological charges and show that the low-energy optical conductivity of the Bogoliubov Fermi surfaces depends crucially on their secondary topological charge. Finally, we discuss the implications of our results to the stability of the superconducting state.

show abstract

Section: Discussionsupporting

confidence: 93%

Many-body selection rule for quasiparticle pair creations in centrosymmetric superconductors

Ahn,

Nagaosa

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…where the overline symmetrizes the expression as ABC = (ABC + ACB + BAC + BCA + CAB + CBA)/3!, for example. These operators are referred to as monopole (N ), dipole (M µ ), quadrupole (Q λ ), and octupole (T ξ ) in accordance with the number of multiplied angular momenta [26,31]. The further high-rank tensors are zero.…”

Section: Appendix A: Complete Basis Set With Spin-orbit Couplingmentioning

confidence: 99%

“…If we restrict ourselves to the j eff = 3/2 diagonal subspace, the matrices are the same as those used in Ref. [31].…”

Section: Appendix A: Complete Basis Set With Spin-orbit Couplingmentioning

confidence: 99%

Multipolar ordering in the three-orbital Hubbard model

Chikano,

Hoshino,

Shinaoka

2021

Preprint

Self Cite

View full text Add to dashboard Cite

The ground-state phase diagrams of the three-orbital t2g Hubbard model are studied using a Hartree-Fock approximation. First, a complete set of multipolar order parameters for t2g models defined in terms of the effective total angular momentum j eff are theoretically derived. These order parameters can classify off-diagonal orders between j eff = 1/2 and j eff = 3/2 manifolds. Second, through extensive Hartree-Fock calculations, the ground-state phase diagrams in the space of (1) the onsite Coulomb repulsion U , (2) the spin-orbit coupling (SOC) λ, and (3) the number of electrons n are mapped out. A variety of nontrivial quantum phases with j eff -diagonal and j eff -off-diagonal multipole orders are found. Finally, future studies using more numerically expensive methods, such as dynamical mean-field theory are discussed.

show abstract

“…Further experimental signatures of BFSs [6] and their instability against spontaneous breaking of inversion symmetry either electronically [7][8][9] or by lattice distortions [10] have been considered by several groups. BFSs can be protected by multiple topological invariants [2,11], which imposes constraints on how they can merge and gap out for strong coupling.…”

Section: Introductionmentioning

confidence: 99%

Symmetry, nodal structure, and Bogoliubov Fermi surfaces for nonlocal pairing

Timm,

Bhattacharya

2021

Preprint

View full text Add to dashboard Cite

Multiband effects can lead to fundamentally different electronic behavior of solids, as exemplified by the possible emergence of Fermi surfaces of Bogoliubov quasiparticles in centrosymmetric superconductors which break time-reversal symmetry. We extend the analysis of possible pairing symmetries, the corresponding nodal structure, and the Bogoliubov Fermi surfaces in two directions: We include nonlocal pairing and we consider internal degrees of freedom other than the effective angular momentum of length j = 3/2 examined so far. Since our main focus is on the Bogoliubov Fermi surfaces we concentrate on even-parity pairing. The required symmetry analysis is illustrated for several examples, as a guide for the reader. We find that the inclusion of nonlocal pairing leads to a much larger range of possible pairing symmetries. For infinitesimal pairing strength, we find a simple yet powerful criterion for nodes in terms of a scalar product of form factors.

show abstract

Electronic multipoles and multiplet pairs induced by Pomeranchuk and Cooper instabilities of Bogoliubov Fermi surfaces

Cited by 25 publications

References 51 publications

Many-body selection rule for quasiparticle pair creations in centrosymmetric superconductors

Many-body selection rule for quasiparticle pair creations in centrosymmetric superconductors

Multipolar ordering in the three-orbital Hubbard model

Symmetry, nodal structure, and Bogoliubov Fermi surfaces for nonlocal pairing

Contact Info

Product

Resources

About