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1970年,Esaki和Lsu提出了半导体超晶格的概念,旨在获得一个全新物理范畴的电子性质.由于超晶格中电子态之间的耦合,导致微带形成,载流子在这些微带中的输运将展现出新的物理现象,例如,Esaki和Lsu所预言的负微分电导效应.然而,后来在超晶格中载流子纵向输运实验上所观察到的低温条件下的负微分电导效应是由于高场畴或者级连共振隧穿引起的.最近,Sibille等人在GaAs/AlAs短周期超晶格中在室温条件下观察到Esaki-Lsu所预言的负微分电导效应.在本文中,我们给出了GaAs/Al_0.3Ga_0.7As短周期超晶格在300K和77K温度下的微带输运实验结果,两个温度下的实验数据均表现出清楚的负微分电导效应,而且77K温度下的微带电导明显地大于300K下的微带电导,这与理论的预言是相符的.
In 1970, Esaki and Lsu proposed the concept of semiconductor superlattices in order to obtain the electronic properties of a completely new physical category. As a result of the coupling between the electronic states in the superlattice, microstrips are formed and carriers flow in these microstrips Transport will exhibit new physical phenomena such as the negative differential conductance predicted by Esaki and Lsu.However, the later negative charge conditions observed in the longitudinal transport experiments of carriers in superlattices Differential conductance effects are due to high-field or cascaded resonant tunneling. Recently, Sibille et al. Observed the negative derivative conductance predicted by Esaki-Lsu at room temperature in a GaAs / AlAs short-period superlattice. At In this paper, we give the experimental results of the microstrip transport of GaAs / Al_3Ga_0.7As short-period superlattices at 300K and 77K. The experimental data at both temperatures show a clear negative differential conductance effect, Moreover, the microstrip conductance at 77K is significantly larger than the microstrip conductance at 300K, which is consistent with the theoretical predictions.