Skyrme insulators: insulators at the brink of superconductivity

Abstract

Current theories of superfluidity are based on the idea of a coherent quantum state with topologically protected, quantized circulation. When this topological protection is absent, as in the case of ${}^3$He-A, the coherent quantum state no longer supports persistent superflow. Here we argue that the loss of topological protection in a superconductor gives rise to an insulating ground state. We specifically introduce the concept of a Skyrme insulator to describe the coherent dielectric state that results from the topological failure of superflow carried by a complex vector order parameter. We apply this idea to the case of SmB${}_6$, arguing that the observation of a diamagnetic Fermi surface within an insulating bulk can be understood in terms of a Skyrme insulator. Our theory enables us to understand the linear specific heat of SmB${}_6$ in terms of a neutral Majorana Fermi sea and leads us to predict that in low fields of order a Gauss, SmB6 will develop a Meissner effect.

10 pages, 4 figures

References in corpus (8)

• Color superconductivity in dense quark matter
• Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
• Kondo Breakdown in Topological Kondo Insulators
• Pair Density Wave correlations in the Kondo-Heisenberg Model
• Excitons in topological Kondo insulators - theory of thermodynamic and transport anomalies in SmB${}_6$
• Anomalous 3D bulk AC conduction within the Kondo gap of SmB${}_6$ single crystals
• Majorana Fermi Sea in Insulating SmB6: A proposal and a Theory of Quantum Oscillations in Kondo Insulators
• The filled skutterudite CeOs${}_4$As${}_{12}$: a hybridization gap semiconductor

Cited by in corpus (64)

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• Mixed-valence insulators with neutral Fermi surfaces
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• Quantum oscillations in insulators with neutral Fermi surfaces
• Fermi surfaces in Kondo insulators
• Quantum oscillations in flux-grown SmB6 with embedded aluminum
• Unconventional thermal metallic state of charge-neutral fermions in an insulator
• Robustness of the Insulating Bulk in the Topological Kondo Insulator SmB${}_6$
• Unusual high-field metal in a Kondo insulator
• Exceeding the Landau superflow speed limit with topological Bogoliubov Fermi surfaces
• Colloquium: Quantum skyrmionics
• Majoranas in mixed-valence insulators
• Anomalous Conductance Oscillations in the Hybridization Gap of InAs/GaSb Quantum Wells
• A solvable 3D Kondo lattice exhibiting odd-frequency pairing and order fractionalization
• Quantum oscillations in strongly correlated topological Kondo insulators
• Order Fractionalization in a Kitaev-Kondo model
• Properties of the donor impurity band in mixed valence insulators
• Quantum oscillations in interaction-driven insulators
• Visualizing the atomic-scale origin of metallic behavior in Kondo insulators
• Quantum oscillations in 2D insulators induced by graphite gates
• Cyclotron resonance inside the Mott gap: a fingerprint of emergent neutral fermions
• Intrinsic bulk quantum oscillations in a bulk unconventional insulator SmB${}_6$
• $f$-electron hybridised metallic Fermi surface in magnetic field-induced metallic YbB${}_{12}$
• Critical role of magnetic moments in heavy-fermion materials: revisiting mysteries of SmB${}_6$
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• Hall anomaly, Quantum Oscillations and Possible Lifshitz Transitions in Kondo Insulator YbB${}_{12}$: Evidence for Unconventional Charge Transport
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• Bulk Rotational Symmetry Breaking in Kondo Insulator SmB6
• Diamagnetic Sm${}^{3+}$ in the topological Kondo insulator SmB${}_6$
• Enhanced quantum oscillations in Kondo insulators
• Quadrupolar spin liquid, octupolar Kondo coupling and odd-frequency superconductivity in an exactly solvable model
• Nonequilibrium Magnetic Oscillation with Cylindrical Vector Beams
• Topological Kondo semimetal and insulator in AB-stacked heterobilayer transition metal dichalcogenides
• Effective model and Magnetic Properties of the Resistive Electron Quadrupling State
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• Charge-Neutral Electronic Excitations in Quantum Insulators
• Charge neutral fermions and magnetic field driven instability in insulating YbIr${}_3$Si${}_7$
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• Extraordinary Bulk Insulating Behavior in the Strongly Correlated Materials FeSi and FeSb${}_2$
• Topologically enabled superconductivity
• Finite temperature physics of $1D$ topological Kondo insulator: Stable Haldane phase, Emergent energy scale and Beyond
• Correlated Topological Mixed-Valence Insulators in Moiré Hetero-Bilayers
• Fluctuation-dominated quantum oscillations in excitonic insulators
• Anomalies in a slightly doped insulator with strong particle-hole asymmetry and narrow gap---the case for SmB${}_6$?
• Quantum Oscillations in an Impurity-Band Anderson Insulator
• Low-energy excitations and transport functions of the one-dimensional Kondo insulator
• Slow crystalline electric field fluctuations in the Kondo lattice SmB${}_6$
• The Detection of Unconventional Quantum Oscillations in Insulating 2D Materials
• Robust hybridization gap in a Kondo Insulator YbB${}_{12}$ probed by femtosecond optical spectroscopy
• Magnetic effects on Chern Kondo insulator
• A Mean-Field Study of Quantum Oscillations in Two-Dimensional Kondo Insulators
• Exotic quantum statistics and thermodynamics from a number-conserving theory of Majorana fermions
• Quantum oscillations in the heat capacity of Kondo insulator YbB12
• Understanding one-dimensional topological Kondo insulator: Poor man's non-uniform antiferromagnetic mean-field theory versus quantum Monte Carlo simulation
• Enhancement of charge-neutral fermionic excitation near spin-flop transition\\ in magnetic Kondo material YbIr${}_3$Si${}_7$
• Observation of the superconducting proximity effect from surface states in SmB${}_6$/YB${}_6$ thin film heterostructures via terahertz spectroscopy
• Signatures of a Majorana-Fermi surface in the Kitaev magnet Ag${}_3$LiIr${}_2$O${}_6$