Hall anomaly and moving vortex charge in layered superconductors

Magnetotransport theory of layered superconductors in the flux flow steady state is revisited. Longstanding controversies concerning observed Hall sign reversals are resolved. The conductivity separates into a Bardeen-Stephen vortex core contribution, and a Hall conductivity due to moving vortex charge. This charge, which is responsible for Hall anomaly, diverges logarithmically at weak magnetic field. Its values can be extracted from magetoresistivity data by extrapolation of vortex core Hall angle from the normal phase. Hall anomalies in YBa_22Cu_33O_{7}7, Bi_22Sr_22CaCu_22O_{8-x}8−x, and Nd_{1.85}1.85Ce_{0.15}0.15CuO_{4-y}4−y data are consistent with theoretical estimates based on doping dependence of London penetration depths. In the appendices, we derive the Streda formula for the hydrodynamical Hall conductivity, and refute previously assumed relevance of Galilean symmetry to Hall anomalies.

The Quantuam Melting Transitions with the Magnetic Field in Weakly Disordered Josephson Junction Arrays

Using the resistively shunted junction model, we study the magnetic field induced dynamic melting transitions of a current-driven vortex system in two-dimensional weakly disordered Josephson junction arrays at zero temperature. From the unified model simulations, we find that the intrinsic quantum vortex liquid (QVL) phenomenon, which consistent with the recent experimental reports in disordered and superconducting MoGe films. The enhancement of critical current in the QVL phase arises from intrinsic quantum fluctuations in the moving vortex flow.