Topological nodal line in superfluid ${}^3$He and the Anderson theorem

Abstract

Superconductivity and superfluidity with anisotropic pairing -- such as $d$-wave in cuprates and $p$-wave in superfluid ${}^3$He -- are strongly suppressed by impurities. Meanwhile, for applications, the robustness of Cooper pairs to disorder is highly desired. Recently, it has been suggested that unconventional systems become robust if the impurity scattering mixes quasiparticle states only within individual subsystems obeying the Anderson theorem that protects conventional superconductivity. Here, we experimentally verify this conjecture by measuring the temperature dependence of the energy gap in the polar phase of superfluid ${}^3$He. We show that oriented columnar non-magnetic defects do not essentially modify the energy spectrum, which has a Dirac nodal line. Although the scattering is strong, it preserves the momentum along the length of the columns and forms robust subsystems according to the conjecture. This finding may stimulate future experiments on the protection of topological superconductivity against disorder and on the nature of topological fermionic flat bands.

arXiv comment17 pages, 10 figures, improved after the referees comments

References in corpus (45)

• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• High-temperature surface superconductivity in topological flat-band systems
• Electric field tunable unconventional superconductivity in alternating twist magic-angle trilayer graphene
• Localization of preformed Cooper-pairs in disordered superconductors
• Topological phases and surface flat bands in superconductors without inversion symmetry
• Quartz Tuning Fork: Thermometer, Pressure- and Viscometer for Helium Liquids
• Bogoliubov Fermi surfaces in superconductors with broken time-reversal symmetry
• Disorder Effects in Two-Dimensional d-wave Superconductors
• The Nonlinear Meissner Effect in Unconventional Superconductors
• Graphite, graphene and the flat band superconductivity
• Observation of half-quantum vortices in topological superfluid 3He
• Polar phase of superfluid 3He in anisotropic aerogel
• Half-quantum vortices and walls bounded by strings in the polar-distorted phases of topological superfluid ${}^3$He
• Topological Ultranodal pair states in iron-based superconductors
• Evidence for a Spatially-Modulated Superfluid Phase of ${}^3$He under Confinement
• Generalized Anderson's theorem for superconductors derived from topological insulators
• Stabilized Pair Density Wave via Nanoscale Confinement of Superfluid ${}^3$He
• Disorder-induced exceptional points and nodal lines in Dirac superconductors
• Exceeding the Landau superflow speed limit with topological Bogoliubov Fermi surfaces
• Influence of Magnetic Scattering on Superfluidity of 3He in Nematic Aerogel
• Analog of Anderson theorem for the polar phase of liquid 3He in nematic aerogel
• The Superfluid Glass Phase of 3He-A
• Nodal points of Weyl semimetals survive the presence of moderate disorder
• Electron irradiation effects on superconductivity in PdTe${}_2$: an application of a generalized Anderson theorem
• The Global Phase Diagram of disordered Higher-order Weyl Semimetals
• Quantitative analytical theory for disordered nodal points [Article and Erratum]
• Fragility of surface states in topological superfluid ${}^3$He
• Energy Gap Induced by Impurity Scattering: New Phase Transition in Anisotropic Superconductors
• Dimensional crossover of effective orbital dynamics in polar distorted 3He-A: Transitions to anti-spacetime
• Robustness of unconventional $s$-wave superconducting states against disorder
• Superfluid 3He in Aerogel
• Propagation of thermal excitations in a cluster of vortices in superfluid 3He-B
• Superfluid 3He in squeezed nematic aerogel
• General theory of robustness against disorder in multi-band superconductors
• Spin, orbital, Weyl and other glasses in topological superfluids
• Using Disorder to Identify Bogoliubov Fermi-Surface States
• The Effect of Magnetic Impurities on Superfluid ${}^3$He in Aerogel
• Half-Quantum Vortices in Nematic and Chiral Phases of ${}^3$He
• Effect of Magnetic Scattering on Superfluid Transition of 3He in Nematic Aerogel
• Impact of Strong Anisotropy on Phase Diagram of Superfluid ${}^3$He in Aerogels
• Effect of boundary condition on Kapitza resistance between superfluid ${}^3$He-B and sintered metal
• Textures of Superfluid 3He-B in Applied Flow and Comparison with Hydrostatic Theory
• Multifractally-enhanced superconductivity in two-dimensional systems with spin-orbit coupling
• Effects of ${}^4$He film on quartz tuning forks in ${}^3$He at ultra-low temperatures
• Supercurrent-Induced Weyl Superconductivity

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• Robustness of unconventional $s$-wave superconducting states against disorder
• Type-II Weyl semimetal vs gravastar
• Vortex-bound solitons in topological superfluid ${}^3$He
• Disorder-dependent superconducting pairing symmetry in doped graphene
• Quantum turbulence and Planckian dissipation
• Superfluid phase transition of nanoscale-confined helium-3
• Two-dimensional flat band on the (011) surface of UTe${}_2$: Implication for STM measurements with a superconducting tip
• Quantum Fluctuations and Multifractally-Enhanced Superconductivity in Disordered Thin Films