Pinning effect and the quantum nature of the dislocation motion in the impurity-free solid

研究了大多数量子固体（bcc solid ^3He）中的位错运动。当施加的应变超过临界值时，位错线开始移动。固体^3He几乎是研究位错运动的理想晶体，因为杂质可以被去除到0.001 ppm，而且通过改变固体的摩尔体积可以调节佩尔斯电位。因此，可以在不受杂质束缚的情况下研究位错运动。我们用高q扭振技术测量了剪切模量和能量耗散作为应变幅值的函数。我们的振荡器非常灵敏，可以在应变幅度从10^<-5>到10^<-8>的范围内测量剪切模量和耗散。确定了培氏势与摩尔体积的关系。观察到位错网络节点的钉住效应。并且在熔点附近观察到固体的剪切模量异常，这是固体的一个特征。

The dislocation motion in most quantum solid, bcc solid ^3He, has been studied. The dislocation line begins to move when the applied strain exceeds the critical value. Solid ^3He is almost an ideal crystal for the study of the dislocation motion because of the facts that the impurities can be removed down to 0.001 ppm and the Peierls potential is tunable by changing the molar-volume of the solid. Therefore, it is possible to study the dislocation motion without the pinning by the impurities.We have measured the shear modulus and the energy dissipation using the high-Q torsional oscillator technique as a function of the strain amplitude. Our oscillator is found to be so sensitive that the shear modulus and the dissipation can be measured at the strain amplitude ranging from 10^<-5> down to 10^<-8>. The molar-volume dependence of the Peieris potential is determined. The pinning effect by the dislocation network nodes is observed. And the anomaly of the shear modulus which is a feature of the solid state has been observed near the melting point.