标题： 电子-空穴双层中由于激子形成引起的异常库仑拖拽 显示英文标题

标题： Anomalous Coulomb Drag in Electron-Hole Bilayers due to the Formation of Excitons

摘要： 最近的几项实验报告了电子-空穴双层中库仑拖曳效应的异常温度依赖性。 受这些令人困惑的数据启发，我们从理论上研究了一种低密度的电子-空穴双层，其中电子和空穴通过形成激子分子来避免量子简并。 我们描述了电子-空穴等离子体和激子气体之间的电离-复合交叉，并计算了层内电阻率和拖曳电阻率随温度的变化。 后者在低温下表现出一个最小值，随后出现急剧上升，在定性上与实验观察结果一致[例如，J. A. Seamons 等人，Phys. Rev. Lett. 102, 026804 (2009)]。 重要的是，在所提出的场景中，拖曳电阻率对电子和空穴浓度不匹配的敏感性较低，这与电子-空穴库珀对场景形成鲜明对比。 显示英文摘要

摘要： Several recent experiments have reported an anomalous temperature dependence of the Coulomb drag effect in electron-hole bilayers. Motivated by these puzzling data, we study theoretically a low-density electron-hole bilayer, where electrons and holes avoid quantum degeneracy by forming excitonic molecules. We describe the ionization-recombination crossover between the electron-hole plasma and exciton gas and calculate both the intralayer and drag resistivity as a function of temperature. The latter exhibits a minimum followed by a sharp upturn at low temperatures in a qualitative agreement with the experimental observations [see, e.g., J. A. Seamons et al., Phys. Rev. Lett. 102, 026804 (2009)]. Importantly, the drag resistivity in the proposed scenario is found to be rather insensitive to a mismatch in electron and hole concentrations in sharp contrast to the scenario of electron-hole Cooper pairing.