石墨烯中位错的Berry相和谷守恒退相干
The Berry phase of dislocations in graphene and valley conserving decoherence
摘要：
我们表明，在石墨烯晶格中的位错引起电子贝里阶段相当于量子化值{0，1/3，-1/3}的单位通量量子，但与相反的符号的两个山谷。石墨烯Aharonov-Bohm环的基本尺度考虑在两端配备有谷滤波器，环绕位错，认为在谷间平均自由程与谷内相位相干长度相比大的情况下，使得谷量子数可以被认为在相关尺度上守恒，对拓扑相位敏感的相干谷极化电流必须在两个谷起作用之前多次穿过器件，而这在中间温度下是不可能的，在中间温度下，后者的长度变成器件尺寸的量级，从而导致明显违反线性传输的基本定律，即在所施加的通量中，磁导是均匀的。我们讨论这种差异的费曼路径图片的退相，解决从量子到经典耗散传输的过渡。我们还调查了这个设备中的散射矩阵形式主义，占退相干的影响，由Buttiker移相电压探针型模型，其中保存的山谷，在那里的磁导仍然是即使在磁通量，也当不同的退相干时间被允许为个人，时间反转连接，山谷。
英文摘要：
We demonstrate that dislocations in the graphene lattice give rise to electron Berry phases equivalent to quantized values {0,1/3,-1/3} in units of the flux quantum, but with an opposite sign for the two valleys. An elementary scale consideration of a graphene Aharonov-Bohm ring equipped with valley filters on both terminals, encircling a dislocation, says that in the regime where the intervalley mean free path is large compared to the intravalley phase coherence length, such that the valley quantum numbers can be regarded as conserved on the relevant scale, the coherent valley-polarized currents sensitive to the topological phases have to traverse the device many times before both valleys contribute, and this is not possible at intermediate temperatures where the latter length becomes of order of the device size, thus leading to an apparent violation of the basic law of linear transport that magnetoconductance is even in the applied flux. We discuss this discrepancy in the Feynman path picture of dephasing, when addressing the transition from quantum to classical dissipative transport. We also investigate this device in the scattering matrix formalism, accounting for the effects of decoherence by the Buttiker dephasing voltage probe type model which conserves the valleys, where the magnetoconductance remains even in the flux, also when different decoherence times are allowed for the individual, time reversal connected, valleys.
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