Barts Evgenii, Tenzin Karma, Sławińska Jagoda
Zernike Institute for Advanced Materials, University of Groningen, 9747AG, Groningen, The Netherlands.
Department of Physical Science, Sherubtse College, Royal University of Bhutan, 42007 Kanglung, Trashigang, Bhutan.
Nat Commun. 2025 Apr 30;16(1):4056. doi: 10.1038/s41467-025-59143-0.
Efficient conversion between charge currents and spin signals is crucial for realizing magnet-free spintronic devices. However, the strong spin-orbit coupling that enhances this conversion also causes rapid spin dissipation, making spin signals difficult to control. Although modern materials science offers novel systems with diverse spin configurations of conduction electrons, understanding their fundamental limitations requires insights into the mechanisms behind the creation and relaxation of spin populations. In this study, we demonstrate that parallel spin-momentum entanglement at the Fermi surface of chiral tellurium crystals gives rise to slow collective relaxation modes, termed relaxons. These relaxons dominate the electrically generated spin and orbital angular momentum accumulation in tellurium, achieving an extraordinary 50% conversion efficiency, and are responsible for a long lifetime of the spin population. We show that the slow relaxons carrying spin density closely resemble the persistent helical spin states observed in GaAs semiconductor quantum wells. This similarity suggests that slow relaxons are a general phenomenon, potentially present in other chiral materials with strong spin-momentum locking, and could be used to generate and transmit spin signals with low heat losses in future electronics.
电荷电流与自旋信号之间的高效转换对于实现无磁自旋电子器件至关重要。然而，增强这种转换的强自旋 - 轨道耦合也会导致快速的自旋耗散，使得自旋信号难以控制。尽管现代材料科学提供了具有多种传导电子自旋构型的新型系统，但要理解它们的基本局限性，需要深入了解自旋群体产生和弛豫背后的机制。在本研究中，我们证明了手性碲晶体费米面上的平行自旋 - 动量纠缠会产生缓慢的集体弛豫模式，称为弛豫子。这些弛豫子主导了碲中电产生的自旋和轨道角动量积累，实现了高达50%的非凡转换效率，并导致自旋群体具有较长的寿命。我们表明，携带自旋密度的缓慢弛豫子与在砷化镓半导体量子阱中观察到的持久螺旋自旋态非常相似。这种相似性表明，缓慢弛豫子是一种普遍现象，可能存在于其他具有强自旋 - 动量锁定的手性材料中，并可用于在未来电子学中以低热量损失产生和传输自旋信号。
