Vortex-lattice melting in two-dimensional superconducting networks and films.
Vortex-lattice melting in two-dimensional superconducting networks and films.
复制标题
二维超导网络和薄膜中的涡晶格熔化。
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
S. Teitel
中科院分区：
文献类型：
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作者：
M. Franz;S. Teitel
我们在二维（2D）超导网络中进行了广泛的蒙特卡洛研究，用于正方形和蜂窝几何形状。和涡流密度1/2--1/[ITAL Q]的密集系统近似。超导膜。对于这种稀释案例，我们发现了过渡温度[Ital t] [sub [ital c]] [类似于] 1/[ITAL Q]固体相位。脱位理论在2D中介导的融化。虽然我们在[ital t] [sub [ital m]]的涡旋剪切模量中发现不连续的跳跃，这与该theoy是一致的，但我们发现（与该理论相反），过渡是弱的，我们发现没有证据表明该案例几乎是完全沮丧的，我们发现该系统可以用原本完全沮丧的涡流模式来描述。在稀释涡流系统中发现的，固定，浮动和液体缺陷阶段。«更少
We carry out an extensive Monte Carlo study of phase transitions in two-dimensional (2D) superconducting networks, in an applied magnetic field, for square and honeycomb geometries. We consider both systems with a dilute vortex density 1/[ital q], and dense systems near full frustration with vortex density 1/2--1/[ital q]. The dilute case gives the continuum limit as [ital q][r arrow][infinity], and serves as a model for a uniform superconducting film. For this dilute case, we find a transition temperature [ital T][sub [ital c]][similar to]1/[ital q], at which the vortex lattice unpins from the network and forms a floating solid' phase. At a higher temperature [ital T][sub [ital m]], this floating solid melts into a vortex liquid. We analyze the transition at [ital T][sub [ital m]] according to the Kosterlitz-Thouless theory of dislocation mediated melting in 2D. While we find a discontinuous jump in the vortex shear modulus at [ital T][sub [ital m]] which is consistent with this theoy, we find (in opposition to this theory) that the transition is weakly first order, and we find no evidence for a hexatic liquid phase. For the case near full frustration, we find that the system can be described in terms of the densitymore » of defects in an otherwise fully frustrated vortex pattern. These dilute defects result in similar behavior as that found in the dilute vortex system, with pinned, floating, and liquid defect phases.« less