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量子点接触中磁性杂质的形成

Magnetic impurity formation in quantum point contacts
课程网址: http://videolectures.net/slonano07_rejec_mif/  
主讲教师: Tomaž Rejec
开课单位: 卢布尔雅那大学
开课时间: 2008-01-18
课程语种: 英语
中文简介:
量子点接触(QPC)是分隔两个较宽电子储存器的窄区域,是亚微米器件的标准构建块,例如量子点小电子盒,并且是量子计算机的基本元素。作为其宽度的函数,通过QPC的电导以G0 = 2e2 / h的整数步长变化,表示其横向模式的量化。这样的测量还显示出额外的肩部,其值约为0.7×G0,这已被称为0.7异常。最近有人提出,如果在低密度下调用QPC中存在磁性杂质,可以解释这种现象。在这里,我们报告了我们广泛的密度函数计算,揭示了在非常一般的条件下,当密度增加到夹断以上时,在通道中形成具有自旋1/2磁矩的电子态。
课程简介: A quantum point contact (QPC), a narrow region separating two wider electron reservoirs, is the standard building block of sub-micron devices, such as quantum dots - small boxes of electrons, and qubits - the proposed basic elements of quantum computers. As a function of its width, the conductance through a QPC changes in integer steps of G0 = 2e2/h, signalling the quantization of its transverse modes. Such measurements also reveal an additional shoulder at a value around 0.7 × G0 which has become known as the 0.7 anomaly. Recently it has been suggested that this phenomenon can be explained if one invokes the existence of a magnetic impurity in the QPC at low densities. Here we report on our extensive density functional calculations that reveal the formation of an electronic state with a spin-1/2 magnetic moment in the channel as the density increases above pinch-off, under very general conditions.
关 键 词: 量子点接触; 电子储存器; 标准构建块
课程来源: 视频讲座网
最后编审: 2019-09-21:cwx
阅读次数: 52