界面轨道杂化效应对磁电耦合影响的量化计算方法
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近些年来，谷电子学的兴起，为人们开启了信息存储的新大门。但长期以来，对于谷电子学的研究均基于材料内部的铁磁交换作用，这导致当下的谷电子学器件基本都需要外加磁场的调控。而事实上，外加磁场的方式，使得器件存在能耗高、器件体积过大等问题。为此寻找一种电场调控的谷电子学器件是十分有意义的。我们面向电控谷极化的方向，致力于解决下一代信息存储等问题，展开了相关研究。通过第一性原理计算，我们预测了MnPS3/CuInP2S6异质结具有铁谷性，在其k+与k-谷之间存在约10 meV的谷极化，且CuInP2S6的极化翻转会导致能谷的翻转，这样以来，就可以在器件水平上实现利用电场调控谷极化。计算还表明，MnPS3/CuInP2S6异质结存在着旋光选择性吸收，即左旋光和右旋光的能量吸收光谱不同，这意味着，实验上可以直接通过施加旋光，即可读取当前器件所处的谷极化状态。该研究为实现电控谷极化信息存储器件的制备提供了一定的理论支持。
In recent years, the emergence of valleytronics has opened a new frontier in information storage research. However, for a long time, valleytronics studies have been grounded in the ferromagnetic exchange interactions within materials, which means that nearly all current valleytronic devices rely on external magnetic field modulation. Unfortunately, this method of magnetic field control brings about notable issues including high energy consumption and excessively large device sizes. Therefore, developing electric-field-controlled valleytronic devices holds great research significance. Guided by the goal of realizing electric-field-controlled valley polarization, we have conducted relevant research aimed at addressing challenges such as next-generation information storage. Through first-principles calculations, we predict that the MnPS3/CuInP2S6 heterojunction exhibits ferrovalley behavior, with a valley polarization of approximately 10 meV between its k+ and k- valleys. Moreover, the polarization reversal of CuInP2S6 will induce the reversal of the valley states, thereby enabling electric-field modulation of valley polarization at the device level. Our calculations further reveal that the MnPS3/CuInP2S6 heterojunction exhibits selective absorption of circularly polarized light: the energy absorption spectra differ between left-handed and right-handed circularly polarized light. This implies that the valley polarization state of the device can be directly read out experimentally by applying circularly polarized light. This research provides valuable theoretical support for the fabrication of electric-field-controlled valley polarization information storage devices.
