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arXiv 1503.06545cond-mat.stat-mech
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关联无序双原子链的热传导

Heat conduction in diatomic chains with correlated disorder

Alexander V. Savin, Vadim Zolotarevskiy, Oleg V. Gendelman

摘要:

本文考虑一维双原子晶格中的热输运,其中含有等量的不同质量的粒子。链中粒子的排序由单个相关参数决定-两个相邻粒子具有相同质量的概率。当这个参数从零增长到1时,链的结构从规则的交错链变化到完全随机的结构,然后--到质量相等的很长的粒子簇。因此,该相关性参数允许控制链中的典型集群大小。为了探讨不同制度的热输运,两个原子间的潜力被认为是。第一种是无限势壁,对应于相邻粒子间的瞬时弹性碰撞。在均质链中,这种相互作用导致异常的热传输。另一种是经典的Lennard-Jones相互作用势,它导致正常的热输运。模拟结果表明,粒子排列的相关无序并不改变热传导系数的收敛特性,但从本质上修改了它的值。对于碰撞势,人们观察到固定链长的系数的本质增长作为大的均匀集群的极限接近。在这些模型中的热输运仍然是超扩散。在Lennard-Jones链中,相关效应在低温极限下似乎不是单调的。这种行为源于上述长团簇的形成与接近交错有序态的安德森局域化之间的竞争。

英文摘要:

The paper considers heat transport in diatomic one-dimensional lattices, containing equal amounts of particles with different masses. Ordering of the particles in the chain is governed by single correlation parameter -- the probability for two neighboring particles to have the same mass. As this parameter grows from zero to unity, the structure of the chain varies from regular staggering chain to completely random configuration, and then -- to very long clusters of particles with equal masses. Therefore, this correlation parameter allows a control of typical cluster size in the chain. In order to explore different regimes of the heat transport, two interatomic potentials are considered. The first one is an infinite potential wall, corresponding to instantaneous elastic collisions between the neighboring particles. In homogeneous chains such interaction leads to an anomalous heat transport. The other one is classical Lennard-Jones interatomic potential, which leads to a normal heat transport. The simulations demonstrate that the correlated disorder of the particle arrangement does not change the convergence properties of the heat conduction coefficient, but essentially modifies its value. For the collision potential, one observes essential growth of the coefficient for fixed chain length as the limit of large homogeneous clusters is approached. The thermal transport in these models remains superdiffusive. In the Lennard-Jones chain the effect of correlation appears to be not monotonous in the limit of low temperatures. This behavior stems from the competition between formation of long clusters mentioned above, and Anderson localization close to the staggering ordered state.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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