美国加州大学洛杉矶分校Qianhui Shi团队研究了WSe2的自旋选择性磁导率。2025年6月9日出版的《自然—物理学》杂志发表了这一最新研究成果。
具有可调自旋选择性电导率的材料系统是自旋电子学技术的关键组成部分。研究组展示了一种自旋选择性输运机制，该机制基于在大磁场下双层WSe2中观察到的不同寻常的朗道能级序列。他们发现，电导率在很大程度上取决于部分填充的朗道能级中具有不同自旋和谷的导电电子与较低能量填充朗道能级的局域电子之间的相对有序性。
研究组观察到，当自旋比和场调谐库仑能量超过临界阈值时，电导率几乎完全被抑制。他们通过调节外部磁场或电场来实现开启和关闭状态之间的切换，许多身体相互作用驱动了一种集体切换机制。与磁阻异质结构相比，这种机制在单一材料内实现了电可调的自旋滤波，这是由位于能量分离自旋和谷极化带中的自由自旋和局域自旋之间的相互作用驱动的。类似的自旋选择性电导率可以在零磁场的平带系统中实现。
附：英文原文
Title: Spin-selective magneto-conductivity in WSe2
Author: Shih, En-Min, Shi, Qianhui, Rhodes, Daniel, Kim, Bumho, Watanabe, Kenji, Taniguchi, Takashi, Yang, Kun, Hone, James, Dean, Cory R.
Issue&Volume: 2025-06-09
Abstract: Material systems that exhibit tunable spin-selective conductivity are key components of spintronic technologies. Here, we demonstrate a mechanism for spin-selective transport that is based on the unusual Landau-level sequence observed in bilayer WSe2 under large applied magnetic fields. We find that the conductivity depends strongly on the relative ordering between conducting electrons with different spins and valleys in a partially filled Landau level and the localized electrons of lower-energy filled Landau levels. We observe that the conductivity is almost completely suppressed when the spin ratio and field-tuned Coulomb energy exceed a critical threshold. We achieve switching between on and off states through either modulation of the external magnetic or electric fields, with many-body interactions driving a collective switching mechanism. In contrast to magnetoresistive heterostructures, this mechanism achieves electrically tunable spin filtering within a single material, driven by the interaction between free and localized spins residing in energy-separated spin-and-valley-polarized bands. Similar spin-selective conductivity may be realizable in flat-band systems at zero magnetic field.
DOI: 10.1038/s41567-025-02918-5
Source: https://www.nature.com/articles/s41567-025-02918-5