Thermodynamic and dynamical signatures of a quantum spin Hall insulator to superconductor transition

The thermodynamic and dynamical properties of a model of Dirac fermions with a deconfined quantum critical point (DQCP) separating an interaction-generated quantum spin Hall insulator from an s-wave superconductor [Liu et al., Nat. Commun. 10, 2658 (2019)] are studied using quantum Monte Carlo simulations. Inside the deconfined quantum critical region bound by the single-particle gap, spinons and spinless charge-2e skyrmions emerge. Since the model conserves total spin and charge, and has a single length scale, these excitations lead to a characteristic linear temperature dependence of the uniform spin and charge susceptibilities. At the DQCP, the order parameter dynamic structure factors show remarkable similarities that support emergent Lorentz symmetry. Above a critical temperature, superconductivity is destroyed by the proliferation of spin-1/2 vortices.

Automated summary

The thermodynamic and dynamical properties of a model of Dirac fermions with a deconfined quantum critical point (DQCP) separating an interaction-generated quantum spin Hall insulator from an s-wave superconductor have been studied. Quantum Monte Carlo simulations were used to investigate the characteristics within the deconfined quantum critical region. Spinons and spinless charge-2e skyrmions were found to emerge within this region. The study also revealed that the model conserves total spin and charge, and has a single length scale, resulting in a linear temperature dependence of the uniform spin and charge susceptibilities. Furthermore, the order parameter dynamic structure factors at the DQCP exhibited remarkable similarities that supported emergent Lorentz symmetry. Additionally, it was observed that the proliferation of spin-1/2 vortices led to the destruction of superconductivity above a critical temperature.