Glazov M M, Golub L E
Ioffe Institute, 194021 St. Petersburg, Russia.
Phys Rev Lett. 2020 Oct 9;125(15):157403. doi: 10.1103/PhysRevLett.125.157403.
Exciton valley Hall effect is the spatial separation of the valley-tagged excitons by a drag force. Usually, the effect is associated with the anomalous velocity acquired by the particles due to the Berry curvature of the Bloch bands. Here we show that the anomalous velocity plays no role in the exciton valley Hall effect, which is governed by the side-jump and skew scattering. We develop a microscopic theory of the exciton valley Hall effect in the presence of a synthetic electric field and phonon drag and calculate all relevant contributions to the valley Hall current also demonstrating the cancellation of the anomalous velocity. The sensitivity of the effect to the origin of the drag force and to the scattering processes is shown. We extend the drift-diffusion model to account for the valley Hall effect and calculate the exciton density and valley polarization profiles.
激子谷霍尔效应是指带谷标记的激子通过拖曳力实现空间分离。通常，该效应与由于布洛赫能带的贝里曲率而使粒子获得的反常速度有关。在此我们表明，反常速度在激子谷霍尔效应中不起作用，该效应由侧跳和斜散射所支配。我们发展了一种在存在合成电场和声子拖曳情况下的激子谷霍尔效应的微观理论，并计算了对谷霍尔电流的所有相关贡献，同时也证明了反常速度的抵消。展示了该效应对拖曳力起源和散射过程的敏感性。我们扩展了漂移 - 扩散模型以考虑谷霍尔效应，并计算了激子密度和谷极化分布。
