arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2407.00517cond-mat.mes-hallcond-mat.mtrl-sci
收藏

轨道-电荷耦合输运中的局部与全局互易性

Local and Global Reciprocity in Orbital-Charge-Coupled Transport

Dongwook Go, Tom S. Seifert, Tobias Kampfrath, Kazuya Ando, Hyun-Woo Lee, Yuriy Mokrousov

AI总结:

本文研究了薄膜中轨道-电荷耦合输运的局部与全局互易性,通过引入proper轨道电流解决传统定义违反互易性的问题,并基于第一性原理计算揭示了W(110)和Pt(111)薄膜中的局部非互易性差异,提出可借此在实验上区分自旋与轨道电流。

摘要:

电荷与轨道角动量(OAM)的耦合输运是轨道电子学的核心。在此,我们研究了薄膜中轨道-电荷耦合输运的互易关系,将体相和表面贡献置于同等地位处理。我们认为轨道电流的传统定义是不妥的,因为由于OAM不守恒,它违反了互易性。通过采用直接与轨道积累相连的所谓“proper”轨道电流,这一问题得以解决。我们建立了轨道与电荷电流之间“全局”(空间积分)响应的互易关系,同时表明它们的“局部”(空间分辨)响应可能存在显著差异。特别是,我们发现了较大的表面贡献,当在局部测量电流时,这可能导致非互易性。这些发现得到了W(110)和Pt(111)薄膜第一性原理计算的支持。在W(110)中,尽管积分响应具有严格的互易性,但轨道-电荷相互转换在层级别上表现出强烈的非互易性。有趣的是,W(110)中的自旋-电荷相互转换即使在局部也基本保持互易性。相比之下,Pt(111)在轨道-电荷和自旋-电荷转换上均表现出局部非互易性,我们将其归因于强自旋轨道耦合。我们提出,这种局部差异可用于在实验上区分自旋和轨道电流。

英文摘要:

The coupled transport of charge and orbital angular momentum (OAM) lies at the core of orbitronics. Here, we examine the reciprocal relation in orbital-charge-coupled transport in thin films, treating bulk and surface contributions on equal footing. We argue that the conventional definition of orbital current is ill-defiled, as it violates reciprocity due to the nonconservation of OAM. This issue is resolved by adopting the so-called \emph{proper} orbital current, which is directly linked to orbital accumulation. We establish the reciprocal relation for the \emph{global} (spatially integrated) response between orbital and charge currents, while showing that their \emph{local} (spatially resolved) responses can differ significantly. In particular, we find large surface contributions that may lead to nonreciprocity when currents are measured locally. These findings are supported by first-principles calculations on W(110) and Pt(111) thin films. In W(110), orbital-charge interconversion is strongly nonreciprocal at the layer level, despite exact reciprocity in the integrated response. Interestingly, spin-charge interconversion in W(110) remains nearly reciprocal even locally. In contrast, Pt(111) exhibits local nonreciprocity for both orbital-charge and spin-charge conversions, which we attribute to strong spin-orbit coupling. We propose that such local distinctions can be exploited to experimentally differentiate spin and orbital currents.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑