Transport signatures of fragile-glass dynamics in the melting of the two-dimensional vortex lattice

Abstract

In two-dimensional (2D) systems, the melting from a solid to an isotropic liquid can occur via an intermediate phase that retains orientational order. However, in 2D superconducting vortex lattices, the effect of orientational correlations on transport, and their interplay with disorder remain open questions. Here we study a 2D weakly pinned vortex system in amorphous MoGe films over an extensive range of temperatures ($\mathbf{T}$) and perpendicular magnetic fields ($\mathbf{H}$) using linear and nonlinear transport measurements. We find that, at low fields, the resistivity obeys the Vogel-Fulcher-Tamman (VFT) form, $\mathbf{\rho }(\mathbf{T})\propto \exp [-\mathbf{W}(\mathbf{H})/(\mathbf{T}-{\mathbf{T}}_0(\mathbf{H}))]$, characteristic of fragile glasses. As $\mathbf{H}$ increases, ${\mathbf{T}}_0(\mathbf{H})$ is suppressed to zero, and a standard vortex liquid behavior consistent with a $\mathbf{T}=0$ superconducting transition is observed. Our findings, supported also by simulations, suggest that the presence of orientational correlations gives rise to a heterogeneous dynamics responsible for the VFT behavior. The effects of quenched disorder become dominant at high $\mathbf{H}$, where a crossover to a strong-glass behavior is observed. This is a new insight into the dynamics of melting in 2D systems with competing orders.

arXiv comment16 pages, 12 figures

References in corpus (17)

• Complexity in Strongly Correlated Electronic Systems
• Supercooled Liquids for Pedestrians
• 2D Melting: From Liquid-Hexatic Coexistence to Continuous Transitions
• The Ginzburg-Landau Theory of Type II superconductors in magnetic field
• Direct observation of melting in a 2-D superconducting vortex lattice
• Enhancement of long range correlations in a 2D vortex lattice by incommensurate 1D disorder potential
• Two-stage magnetic-field-tuned superconductor-insulator transition in underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$
• Vortex Lattice Melting in 2D Superconducting Networks and Films
• Vortices Freeze like Window Glass: the Vortex Molasses Scenario
• Melting of the vortex lattice through intermediate hexatic fluid in a-MoGe thin film
• Vortex lattce melting in 2D superconductors and Josephson arrays
• Commensurate and Incommensurate Vortex Lattice Melting in Periodic Pinning Arrays
• Flux lattice melting and depinning in the weakly frustrated 2D XY model
• Vortex phase diagram and the normal state of cuprates with charge and spin orders
• Extreme sensitivity of the vortex state in a-MoGe films to radio-frequency electromagnetic perturbation
• Domain regime in two-dimensional disordered vortex matter
• Vortex-lattice melting in two-dimensional superconductors in intermediate fields