Elementary excitations in quantum crystals
Elementary excitations in quantum crystals
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量子晶体中的基本激发
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
A. F. Andreev
中科院分区：
文献类型：
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作者：
A. F. Andreev
研究了两个点缺陷在固体氦中的运动特性，这两个点缺陷位于远小于相互作用范围但大于原子间距的位置。发现缺陷受相互作用势的约束。根据相互间距的大小和缺陷相对于晶体轴的排列，有四种可能的情况：1)缺陷进行三维扩散运动，2)它们实际上是静止的，3)它们在晶体的基面上进行二维扩散运动，4)缺陷对表现为一个二维准粒子，作为自由粒子移动，但仅在基面上。结果表明，量子晶体中位错中的扭结转化为自由的一维准粒子。它们的量子力学离域导致了滑移面上带有扭结的位错的离域。给出了低温下扭结扩散系数的估计。
The character of the motion in solid helium of two point defects located at a distance considerably smaller than the range of the interaction but greater than the interatomic spacing is investigated. The defects are found to be bound by the interaction potential. Depending on the magnitude of the mutual spacing and the arrangement of the defects with respect to the crystallographic axes, four cases are possible: 1) The defects perform three-dimensional diffusional motion, 2) they are practically stationary, 3) they perform twodimensional diffusional motion in the basal plane of the crystal, 4) the pair of defects behaves as one twodimensional quasiparticle, moving as a free particle but only in the basal plane. It is shown that kinks in dislocations in the quantum crystal are transformed into free one-dimensional quasiparticles. Their quantum-mechanical delocalization leads to the delocalization of dislocations with kinks in the slip plane. An estimate of the diffusion coefficients of the kinks at low temperatures is given.