Giant Plasticity of a Quantum Crystal
Giant Plasticity of a Quantum Crystal
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DOI：
10.1103/physrevlett.110.035301
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发表时间：
2013-01-14
影响因子：
8.6
通讯作者：
Balibar, Sebastien
中科院分区：
文献类型：
--
作者：
Haziot, Ariel;Rojas, Xavier;Balibar, Sebastien
当在高温下受到大应力时，通常的晶体会发生不可逆变形。这种现象被称为塑性，它是由于运动的晶体缺陷，如位错。我们发现，在没有杂质的情况下，在零温度极限下，氦4晶体呈现出巨大的各向异性和可逆的可塑性。对定向单晶的直接测量表明，由于位错自由地平行于六边形结构的基面滑动，它们的抗剪切能力在一个特定方向上几乎消失。一旦氦3杂质的痕迹与位错结合，或者它们的运动受到热声子碰撞的抑制，这种可塑性就会消失。
When submitted to large stresses at high temperature, usual crystals may irreversibly deform. This phenomenon is known as plasticity and it is due to the motion of crystal defects such as dislocations. We have discovered that, in the absence of impurities and in the zero temperature limit, helium 4 crystals present a giant plasticity that is anisotropic and reversible. Direct measurements on oriented single crystals show that their resistance to shear nearly vanishes in one particular direction because dislocations glide freely parallel to the basal planes of the hexagonal structure. This plasticity disappears as soon as traces of helium 3 impurities bind to the dislocations or if their motion is damped by collisions with thermal phonons.