Bandwidth controlled quantum phase transition between an easy-plane quantum spin Hall state and an s-wave superconductor

Abstract

The quantum spin Hall state can be understood in terms of spontaneous O(3) symmetry breaking. Topological skyrmion configurations of the O(3) order parameter vector carry a charge 2e, and as shown previously, when they condense, a superconducting state is generated. We show that this topological route to superconductivity survives easy-plane anisotropy. Upon reducing the O(3) symmetry to O(2)$\times$ Z${}_2$, skyrmions give way to merons that carry a unit charge. On the basis of large-scale auxiliary field quantum Monte Carlo simulations, we show that at the particle-hole symmetric point, we can trigger a continuous and direct transition between the quantum spin Hall state and s-wave superconductor by condensing pairs of merons. This statement is valid in both strong and weak anisotropy limits. Our results can be interpreted in terms of an easy-plane deconfined quantum critical point. However, in contrast to the previous studies in quantum spin models, our realization of this quantum critical point conserves $U(1)$ charge, such that skyrmions are conserved.

References in corpus (32)

• The electronic properties of graphene
• $Z_2$ Topological Order and the Quantum Spin Hall Effect
• "Deconfined" quantum critical points
• Quantum criticality beyond the Landau-Ginzburg-Wilson paradigm
• Evidence for deconfined quantum criticality in a two-dimensional Heisenberg model with four-spin interactions
• Deconfined quantum critical points: symmetries and dualities
• Theory of interacting electrons on the honeycomb lattice
• Pinning the order: the nature of quantum criticality in the Hubbard model on honeycomb lattice
• Quantum criticality with two length scales
• A sufficient condition for the absence of the sign problem in the fermionic quantum Monte-Carlo algorithm
• Fermionic quantum criticality in honeycomb and $\pi$-flux Hubbard models: Finite-size scaling of renormalization-group-invariant observables from quantum Monte Carlo
• Duality between the deconfined quantum-critical point and the bosonic topological transition
• Striped phase in a quantum XY-model with ring exchange
• Topological spin Hall states, charged skyrmions, and superconductivity in two dimensions
• Deconfined criticality, runaway flow in the two-component scalar electrodynamics and weak first-order superfluid-solid transitions
• Spin Charge Separation in the Quantum Spin Hall State
• A theory of deconfined pseudo-criticality
• Superconductivity from the Condensation of Topological Defects in a Quantum Spin-Hall Insulator
• Dirac Fermions with Competing Orders: Non-Landau Transition with Emergent Symmetry
• Note on Wess-Zumino-Witten models and quasiuniversality in 2+1 dimensions
• Detecting signals of weakly first-order phase transitions in two-dimensional Potts models
• First-order phase transition in easy-plane quantum antiferromagnets
• Phase transition in a 2-dimensional Heisenberg model
• Doping-induced quantum spin Hall insulator to superconductor transition
• Topological Invariant and Quantum Spin Models from Magnetic π Fluxes in Correlated Topological Insulators
• Quantum criticality in the metal-superconductor transition of interacting Dirac fermions on a triangular lattice
• New easy-plane ${\mathbb{CP}}^{N-1}$ fixed points
• First-order superfluid to valence bond solid phase transitions in easy-plane SU($N$) magnets for small-$N$
• Gross-Neveu Heisenberg criticality: dynamical generation of quantum spin Hall masses
• Superfluid Insulator Transitions of Hard-Core Bosons on the Checkerboard Lattice
• Equivalent-neighbor Potts models in two dimensions
• First order phase transitions in the square lattice "easy-plane" J-Q model

Cited by in corpus (1)

• Fermionic skyrmions and bosonization for a Gross-Neveu transition