AI 中文总结
研究 Cr 掺杂的 $\mathrm{RuO_{2}}(110)$ 交替磁体的隧道磁电阻效应，采用第一性原理计算，发现其共线反铁磁结构打破时间反演对称性，动量相关自旋极化与(110)取向使电流自旋极化，计算隧道结 TMR 效应并分析其归因。
AI 中文摘要
反铁磁体在其磁结构打破宏观时间反演对称性时，在动量空间中可具有有限的自旋极化。这种自旋极化即使在净磁化极小的反铁磁体中也能产生自旋极化电流，从而支持反铁磁隧道磁电阻（TMR）效应。本文采用第一性原理计算，研究具有(110)取向的掺杂交替磁体 $\mathrm{Ru}_{1 - x}\mathrm{Cr}_{x}\mathrm{O}_{2}$ 的 TMR 效应，其共线反铁磁结构宏观上打破时间反演对称性。动量相关的自旋极化与(110)晶体取向相结合，使电流通过体相 $\mathrm{Ru}_{1 - x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$ 自旋极化。进一步计算了 $\mathrm{Ru}_{1 - x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)/\mathrm{TiO_{2}}(110)/\mathrm{Ru}_{1 - x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$ 隧道结中的 TMR 效应，发现出现了有限的 TMR 效应。基于隧道输运分析，TMR 效应归因于具有动量依赖性的自旋极化隧道输运、界面磁结构以及 $\mathrm{Ru}_{1 - x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$ 体相形式的自旋极化电流。
英文摘要
Antiferromagnets can have a finite spin-polarization in the momentum space when their magnetic structure breaks the macroscopic time-reversal symmetry. This spin-polarization can produce a spin-polarized electric current even in antiferromagnets with vanishingly small net magnetizaton, which supports the antiferromagentic tunnel magnetoresistance (TMR) effect. In this paper, using first-principles calculations, we study the TMR effect with a doped altermagnet $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}$ with $(110)$ orientation, whose collinear antiferromagnetic structure breaks the time-reversal symmetry macroscopically. The momentum-dependent spin-polarization combined with the $(110)$ crystal orientation makes the electric current spin-polarized through bulk $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$. We further calculate the TMR effect in the $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)/\mathrm{TiO_{2}}(110)/\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$ tunnel junction and show that a finite TMR effect emerges. Based on the analysis of the tunneling transport, the TMR effect is attributed to the spin polarized tunneling transport with momentum dependence and the interfacial magnetic structures, as well as the spin-polarized electric current in a bulk form of $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$.
Comments9 pages, 7 figures
