STU-GTIIT光学论坛（No.56）

报告地点：at lecture hall E508 in the North Campus of GTIIT

报告时间：2025年11月25日 17:00

报告题目: Resistivity of Non-Galilean-Invariant Two-Dimensional Dirac Systems

报告人：Prof. Vadim Kovalev（Institute of Semiconductor Physics, Russian Academy of Sciences）

报告摘要：

We discuss the influence of electron-electron scattering processes on the resistivity of a two-dimensional system with a linear (Dirac) spectrum. In conventional systems with a parabolic spectrum, where umklapp scattering is either prohibited or ineffective due to the small Fermi surface, particle-particle scattering does not contribute to conductivity because it does not change the total momentum. However, within the framework of the Boltzmann kinetic model, we demonstrate that electron-electron scattering in Dirac systems can significantly contribute to conductivity, producing distinct temperature-dependent corrections: a T^4 behavior at low temperatures and a T^2 dependence at moderate temperatures. While the predicted T^4 scaling is not observed experimentally—likely suppressed by dominant weak localization effects—the T^2 scaling is clearly confirmed in experiments. Specifically, temperature-dependent resistivity data from a gapless single-valley HgTe quantum well exhibit T^2 corrections, which align well with theoretical predictions.

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理学院

2025年11月24日