Dynamical Ordering of Driven Stripe Phases in Quenched Disorder

Abstract

We examine the dynamics and stripe formation in a system with competing short and long range interactions in the presence of both an applied dc drive and quenched disorder. Without disorder, the system forms stripes organized in a labyrinth state. We find that, when the disorder strength exceeds a critical value, an applied dc drive can induce a dynamical stripe ordering transition to a state that is more ordered than the originating undriven, unpinned pattern. We show that signatures in the structure factor and transport properties correspond to this dynamical reordering transition, and we present the dynamic phase diagram as a function of strengths of disorder and dc drive. PACS numbers: 64.60. Cn, 89.75.Kd, 73.20.Qt, 71.45.Lr Recently, there has been considerable interest in the dynamics of driven elastic media in the presence of quenched disorder and an applied drive. Physical systems that fall into this category include vortex lattices in disordered superconductors [1][2][3][4][5][6][7][8], sliding charge-density waves [9], driven electron crystals in the presence of random impurities [10], sliding friction [11], and domain wall motion [12]. One of the most studied systems in this class is a vortex lattice driven by an applied current through disordered superconductors. Higgins and Bhattacharya [1] used transport measurements to map out a dynamical phase diagram for driven vortex matter based on transport signatures, and proposed the existence of three dynamical phases: a low drive pinned phase where the vortices do not move, a plastic phase where inhomogeneous flow and tearing of the highly disordered vortex lattice occurs, and an elastic flow regime where the lattice slides as a whole [1]. Koshelev and Vinokur [2] investigated the driven vortex lattice system theoretically and numerically, observed three phases as a function of increasing applied drive, and found that the disordered lattice in the plastic flow regime can undergo a striking dynamical freezing transition in which the vortex lattice reorders at high drives.Further theoretical work has shown that the recrystallized state is not fully ordered but is still strongly affected by transverse modes from the pinning. Thus the reordered state may form a moving smectic lattice with anisotropic ordering, where the vortices move in onedimensional (1D) partially coupled channels aligned with the drive [3][4][5]. This reordering transition to an aligned moving smectic state has been experimentally confirmed by transport [6] and direct imaging [7] experiments. In addition, numerical work has confirmed the presence of a field-driven plastic to ordered or elastic transition [8]. Dynamical reordering has also been studied in sliding charge density waves [9] and driven Wigner crystals [10].A natural question is whether these dynamical phases and reordering transitions can occur in other systems which do not form triangular lattices in the absence of quenched disorder. For example, many systems form "stripe" or "labyrinth" states [13], including diblockcopoly...

Vortex dynamics for low-κtype-II superconductors

“…2b. These two vortex states have been well observed in high-κ systems with pure intervortex repulsion 23,[25][26][27][28][29][30][31] . We thus conclude that for strong pinning and moderate driving forces both for low-κ and high-κ vortex system the driven vortex states are dominated by pinning and that the details of the intervortex interactions are not so important.…”

Depinning and dynamics of ac driven vortex lattices in random media

“…Extensively studied examples are abundant in the literature: moving vortex lattices in type II superconductors, [1][2][3][4][5][6][7][8][9][10][11][12] sliding colloidal particles 13,14 or charge density wave systems, 15 magnetic bubble arrays, 16 driven Wigner crystals, 17,18 and stripe forming systems. 19 Among the topics that have recently received much attention is the nature of the depinning mechanisms that occur as the external dc driving force is increased beyond the critical force F C dc , and its relation with proliferation of topological defects in the form of bounded or unbounded disclinations. The dependence of the dynamics with initial conditions has been examined in detail and it was determined that for dc drives, memory of initial conditions is lost at depinning.…”

Anisotropic sliding dynamics, peak effect, and metastability in stripe systems

“…Typically, as the density increases, the system progresses from a low density clump phase to an intermediate density stripe phase, and then to a higher density bubble phase where organized voids appear in the system; finally, at the highest densities, the particles form a uniform crystal state 4,8,9,19 . In two-dimensional (2D) systems of finite size, a stripe phase containing oriented stripes is often observed 4,5,19 ; however, for larger systems, the strong degeneracy in the stripe ground state orientation can produce a labyrinth pattern composed of many different stripe orientations 3,4,8,20 . The presence of any type of bias produced by the boundaries, a substrate, or an external drive such as a shear breaks the symmetry of the stripe ground state and causes the stripes to align in a single direction 9,20,21 .…”

“…In two-dimensional (2D) systems of finite size, a stripe phase containing oriented stripes is often observed 4,5,19 ; however, for larger systems, the strong degeneracy in the stripe ground state orientation can produce a labyrinth pattern composed of many different stripe orientations 3,4,8,20 . The presence of any type of bias produced by the boundaries, a substrate, or an external drive such as a shear breaks the symmetry of the stripe ground state and causes the stripes to align in a single direction 9,20,21 .…”