Local symmetries and order-disorder transitions in small macroscopic Wigner islands

Abstract

The influence of local order on the disordering scenario of small Wigner islands is discussed. A first disordering step is put in evidence by the time correlation functions and is linked to individual excitations resulting in configuration transitions, which are very sensitive to the local symmetries. This is followed by two other transitions, corresponding to orthoradial and radial diffusion, for which both individual and collective excitations play a significant role. Finally, we show that, contrary to large systems, the focus that is commonly made on collective excitations for such small systems through the Lindemann criterion has to be made carefully in order to clearly identify the relative contributions in the whole disordering process.

Single file diffusion enhancement in a fluctuating modulated quasi-1D channel

“…However, the evolution with T of the diffusion amplitudes differ according to N and a detailed analysis of these differences proves that it is greatly influenced by the relative inter-shell movement. Indeed, we showed in a previous paper that for 11 × 10 11 K≤ T ≤ 12 × 10 11 K, the relative shells' movements are small in the N = 19 system [10]. In the diffusion experiments, one can observe that, in the same range of temperature, the diffusion curves are remarkably roughly superposable (Fig.4).…”

“…Notice that this interaction is exactly similar to the intervortex interaction in superconductors [8,9]. To introduce thermal noise, the whole cell is fixed on loudspeakers supplied by a white noise voltage, this mechanical shaking simulating a tunable effective temperature that is measured in-situ [10]. Throughout the experiments, images of the particles are recorded in real time using a camera.…”

“…This configuration is denoted (1-6-12) hereafter ( Fig.1) [9]. To observe well-defined shells, the experiments have been performed at an effective temperature equal to roughly a few tens of the inter-ball interaction ; for this temperature range, the balls seldom jump from one shell to another [10]. The effective thermal agitation only induces orthoradial motion while the radial displacements are reduced as it can be seen on the balls trajectories presented in the insets of Fig.1 [10].…”

Finite-temperature crossovers in periodic disordered systems

“…In particular, the crossover inverse length scale between the thermal and the Larkin regime is given in Eqs. (12) and (44) while the one between the Larkin and the random periodic is (14) and (41) . Note that, apart from the Lindemann length, the quantity q th does not depend on the dimension of the system, contrarily to q L , which does directly depend on .…”

“…One encompasses interfaces in magnetic [2,3], ferroelectric [4,5] materials or spintronic systems [6], fluid invasion in porous media [7] and fractures [8,9]. The second concerns random periodic systems such as charge-density waves [10], vortex lattices in type II superconductors [11] and Wigner crystals [12]. All these systems are characterized by the competition between an elastic energy that wants the manifold flat or the periodic system ordered and the impurities-that are inevitably present in any real system-that tend to distort it in order to accommodate it in the optimal positions.…”