Quantum Interference Effect in a Periodic System in the Ballistic Region

在4.2K下观察到超高纯度铝单晶的体积残余电阻率、负弯曲电阻和非线性I-V特性与电流取向的关系。此外，在本项目中，在4.2K的超高纯度铝单晶上测量了横向磁电阻中磁击穿引起的量子振荡。在电流方向为[110]的试样中，在B = 4.0 T的磁场中，在晶体取向[001]方向上，观察到磁电阻率线性增加叠加的单调增加振荡。另一方面，在电流方向为[100]的试样中，随着磁场的增加，振荡的底部和顶部及其振幅每三个周期逐步增加，而三个周期之间的振幅单调增加。在这个电流方向上，对1/B振荡的δ (1/B)周期也在每六个周期2.15 * 10^<-2> T^<-1>的平均值附近突然增加和减少。这些振荡的逐步变化是由一种新的电子波的量子干涉效应引起的。

Current-orientation dependence of bulk residual resistivity, negative bend resistance and nonlinear I-V characteristics have been observed in ultrahigh-purity aluminium single crystals at 4.2K.In this project, further, quantum oscillations due to magnetic breakdown in the transverse magnetoresistance have been measured on single crystals of ultrahigh-purity aluminium at 4.2K.In a specimen with the [110] current direction, monotonically increasing oscillations superimposed on the linear increase of magnetoresistivity are observed in magnetic fields up to B = 4.0 T directed in the [001] crystallographic orientation. On the other hand, in a specimen with the [100], current direction, the bottom and the top of the oscillations and their amplitude have been found to increase stepwise every three cycles with increasing magnetic fields, while the amplitude increases monotonically among three cycles. For this current direction, also a sudden increase and decrease in the period DELTA (1/B) of the oscillations against 1/B have been observed around the mean value of 2.15 * 10^<-2> T^<-1> every six cycles. It is suggested that these stepwise changes of the oscillations arises from a new quantum interference effect of electron waves.