The Higgs Mode in Disordered Superconductors Close to a Quantum Phase Transition

Abstract

The concept of mass-generation via the Higgs mechanism was strongly inspired by earlier works on the Meissner-Ochsenfeld effect in superconductors. In quantum field theory, the excitations of longitudinal components of the Higgs field manifest as massive Higgs bosons. The analogous Higgs mode in superconductors has not yet been observed due to its rapid decay into particle-hole pairs. Following recent theories, however, the Higgs mode should decrease below the pairing gap $2\Delta$ and become visible in two-dimensional systems close to the superconductor-insulator transition (SIT). For experimental verification, we measured the complex terahertz transmission and tunneling density of states (DOS) of various thin films of superconducting NbN and InO close to criticality. Comparing both techniques reveals a growing discrepancy between the finite $2\Delta$ and the threshold energy for electromagnetic absorption which vanishes critically towards the SIT. We identify the excess absorption below $2\Delta$ as a strong evidence of the Higgs mode in two dimensional quantum critical superconductors.

6 pages, 3 figures

References in corpus (7)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Nature of the superconductor-insulator transition in disordered superconductors
• Disorder-Induced Inhomogeneities of the Superconducting State Close to the Superconductor-Insulator Transition
• The `Higgs' Amplitude Mode at the Two-Dimensional Superfluid-Mott Insulator Transition
• Quantum Magnets under Pressure: Controlling Elementary Excitations in TlCuCl3
• Phase fluctuations in a strongly disordered s-wave superconductor close to the metal-insulator transition
• Direct observation of the superconducting gap in thin film of titanium nitride using terahertz spectroscopy

Cited by in corpus (28)

• Light-induced emergent phenomena in 2D materials and topological materials
• Phonon driven Floquet matter
• Higgs mode in a strongly interacting fermionic superfluid
• High-temperature superconductivity in one-unit-cell FeSe films
• Electrodynamics of granular aluminum from superconductor to insulator: observation of collective superconducting modes
• Direct observation of the Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point
• Higgs amplitude mode in the vicinity of a $(2+1)$-dimensional quantum critical point: a nonperturbative renormalization-group approach
• Optical signatures of the superconducting Goldstone mode in granular aluminum: experiments and theory
• Granular superconductors for high kinetic inductance and low loss quantum devices
• Lightwave Terahertz Quantum Manipulation of Non-equilibrium Superconductor Phases and their Collective Modes
• Optical conductivity of granular aluminum films near the Mott metal-to-insulator transition
• Superconducting Energy Scales and Anomalous Dissipative Conductivity in Thin Films of Molybdenum Nitride
• Microwave properties of superconductors close to SIT
• Collective dynamics and the Anderson-Higgs mechanism in a bona fide holographic superconductor
• Van Vleck excitons in Ca${}_2$RuO${}_4$
• Structural dynamics in thermal-treatment of amorphous indium-oxide films
• Random telegraph fluctuations in granular microwave resonators
• Localized Higgs modes of superfluid Bose gases in optical lattices: A Guzwiller mean-field study
• Signatures of superconducting Higgs mode in irradiated Josephson junctions
• Local spectroscopies across the superconductor-insulator transition
• Higgs physics in superconductors
• Spatially resolved collective modes in d-wave superconductors
• Topological Higgs Amplitude Modes in Strongly Interacting Superfluids
• Optical conductivity of a dirty current-carrying superconductor
• Direct observation of intrinsic surface magnetic disorder in amorphous superconducting films
• Anomalous terahertz nonlinearity in disordered s-wave superconductor close to the superconductor-insulator transition
• On the relation between disorder and homogeneity in an amorphous metal
• Higgs and Nambu-Goldstone modes in a spin-1 $XY$ model with long-range interactions