发表机构
Aligarh Muslim University（阿利加尔穆斯林大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文统一解析了双层石墨烯中多种散射机制下的输运弛豫率，揭示了泡利阻塞在简并条件下的关键影响，并指出中性杂质散射为主导机制。
AI 中文摘要
我们提出了双层石墨烯（BLG）中载流子输运弛豫的统一解析处理方法，包括表面粗糙度、带电和中性杂质、声学与光学声子以及衬底极性声子的散射。计算在低能双带近似框架内，利用费米黄金规则和半经典玻尔兹曼输运方程进行。推导了输运弛豫率的闭式表达式，并通过相应散射积分的数值评估加以验证。特别关注泡利阻塞，在简并载流子条件下，由于BLG近似抛物线的低能色散和近乎恒定的态密度，其影响变得重要。我们发现，对于悬浮和衬底支撑的BLG，泡利阻塞以机制和能量依赖的方式改变弛豫率。在所考虑的参数下，中性杂质散射在相当大的能量范围内提供主要贡献，而声学声子散射和带电杂质散射仍是重要的竞争机制。光学声子散射在其发射阈值以下被抑制，而衬底极性声子在支撑BLG中提供了额外的弛豫通道。与单层石墨烯和常规二维电子气的比较，突显了能带色散、态密度、屏蔽和手性在决定BLG独特散射行为中的作用。这些结果为BLG输运中主要动量弛豫机制的相对重要性以及泡利阻塞的作用提供了解析见解。
英文摘要
We present a unified analytical treatment of carrier transport relaxation in bilayer graphene (BLG), including scattering by surface roughness, charged and neutral impurities, acoustic and optical phonons, and substrate polar phonons. The calculation is formulated within the low-energy two-band approximation using Fermi's golden rule and the semiclassical Boltzmann transport equation. Closed-form expressions for the transport relaxation rates are derived and verified by numerical evaluation of the corresponding scattering integrals. Particular attention is given to Pauli blocking, whose influence becomes important under degenerate carrier conditions owing to the approximately parabolic low-energy dispersion and nearly constant density of states of BLG. We find that Pauli blocking modifies the relaxation rates in a mechanism- and energy-dependent manner for both suspended and substrate-supported BLG. For the parameters considered, neutral-impurity scattering provides the dominant contribution over a substantial energy range, while acoustic-phonon and charged-impurity scattering remain important competing mechanisms. Optical-phonon scattering is suppressed below its emission threshold, whereas substrate polar phonons provide an additional relaxation channel in supported BLG. Comparison with monolayer graphene and a conventional two-dimensional electron gas highlights the role of band dispersion, density of states, screening, and chirality in determining the distinct scattering behavior of BLG. These results provide analytical insight into the relative importance of the principal momentum-relaxation mechanisms and the role of Pauli blocking in BLG transport.
Comments26 pages, 5 figures
