Quantum Interference Effect in a Periodic System in the Ballistic Region

在4.2K下，观察到了超高纯铝单晶体的体剩余电阻率、负弯曲电阻和非线性I-V特性与电流方向的关系。在此基础上，进一步测量了4.2K下超高纯铝单晶体横向磁电阻中磁击穿引起的量子振荡。在指向[001]晶体取向的高达B = 4.0 T的磁场中，观察到叠加在磁阻线性增加上的单调增加的振荡。另一方面，在[100]，电流方向，底部和顶部的振荡和振幅已被发现逐步增加每三个周期随着磁场的增加，而振幅单调增加之间的三个周期。对于该电流方向，在每六个周期的平均值2.15 * 10^ T^附近也观察到相对于1/B的振荡的周期DELTA（1/B）的突然增加和减少<-2><-1>。这表明，这些逐步变化的振荡来自一个新的量子干涉效应的电子波。

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.