Leggett modes and the Anderson-Higgs mechanism in superconductors without inversion symmetry

Abstract

We develop a microscopic and gauge-invariant theory for collective modes resulting from the phase of the superconducting order parameter in non-centrosymmetric superconductors. Considering various crystal symmetries we derive the corresponding gauge mode ${\omega }_{\mathrm{G}}(\mathbf{q})$ and find, in particular, new Leggett modes ${\omega }_{\mathrm{L}}(\mathbf{q})$ with characteristic properties that are unique to non-centrosymmetric superconductors. We calculate their mass and dispersion that reflect the underlying spin-orbit coupling and thus the balance between triplet and singlet superconductivity occurring simultaneously. Finally, we demonstrate the role of the Anderson-Higgs mechanism: while the long-range Coulomb interaction shifts ${\omega }_{\mathrm{G}}(\mathbf{q})$ to the condensate plasma mode ${\omega }_{\mathrm{P}}(\mathbf{q})$, it leaves the mass ${\Lambda }_0$ of the new Leggett mode unaffected and only slightly modifies its dispersion.

10 pages, 3 figures

References in corpus (4)

• Observation of Leggett's collective mode in a multi-band MgB2 superconductor
• Gap structure in noncentrosymmetric superconductors
• Electronic Raman scattering in non-centrosymmetric superconductors
• Macroscopic quantum tunneling in multigap superconducting Josephson junctions: Escape rate enhancement via quantum fluctuations of Josephson-Leggett mode

Cited by in corpus (18)

• Collective Excitations and Nonequilibrium Phase Transition in Dissipative Fermionic Superfluids
• Theory of light-induced resonances with collective Higgs and Leggett modes in multiband superconductors
• Theoretical Understanding of Photon Spectroscopies in Correlated Materials In and Out of Equilibrium
• Observation of superconducting collective modes from competing pairing instabilities in single-layer NbSe${}_2$
• Strongly correlated Fermi superfluid near an orbital Feshbach resonance: Stability, equation of state and Leggett mode
• Spectroscopic signatures of time-reversal symmetry breaking superconductivity
• Two-band superfluidity and intrinsic Josephson effect in alkaline-earth Fermi gases across an orbital Feshbach resonance
• Chiral Higgs Mode in Nematic Superconductors
• Spin-orbit coupled superconductivity: Rashba-Hubbard model on the square lattice
• Optical response of the Leggett mode in multiband superconductors in the linear response regime
• Classification of Lifshitz invariant in multiband superconductors: an application to Leggett modes in the linear response regime in Kagome lattice models
• Higgs modes in proximized superconducting systems
• Dynamic structure factors of a strongly interacting Fermi superfluid near an orbital Feshbach resonance across the phase transition from BCS to Sarma superfluid
• Optically active Higgs and Leggett modes in multiband pair-density-wave superconductors with Lifshitz invariant
• Coupling the Higgs mode and ferromagnetic resonance in spin-split superconductors with Rashba spin-orbit coupling
• Superconductivity in a two-dimensional repulsive Rashba gas at low electron density
• Unconventional superconductivity in monolayer transition metal dichalcogenides
• Hybrid collective excitations in topological superconductor/ferromagnetic insulator heterostructures