重费米子YbAl $_3$中强的与温度有关的自旋轨道力矩
Strong, Temperature-Dependent Spin-Orbit Torques in Heavy Fermion YbAl$_3$
摘要：
目前正在研究使用电流产生的自旋轨道转矩[1]来驱动磁化动力学，以实现新一代非易失性、低功耗磁存储器。以前的研究主要集中在重金属[2-8]、具有强Rashba相互作用的界面[9，10]和拓扑绝缘体[11-14]产生的自旋轨道扭矩。这些材料家族都可以很好地描述使用模型与非相互作用的电子能带结构。在这里，我们表明强相关重费米子材料（近藤晶格系统YbAl $_{3}$）内的电子相互作用可以大幅增强自旋轨道扭矩。作为从室温到YbAl $_{3}$的相干温度（$T^* \approx 37$ K）的降低温度的函数，自旋扭矩电导率增加约4倍，在较低温度下达到饱和，实现大于任何重金属元素的最大值。这种温度依赖性模拟了近藤机制中由镱4 $f$衍生的重带引起的费米能级态密度在$T^*$处的增加和饱和，如通过角度分辨光电子能谱测量的[15]。因此，我们确定的多体近藤共振的源的大增强的自旋轨道扭矩在YbAl $_{3}$。我们的观察揭示了新的机会，自旋轨道扭矩操纵磁存储器的工程量子多体状态。
英文摘要：
The use of current-generated spin-orbit torques[1] to drive magnetization dynamics is under investigation to enable a new generation of non-volatile, low-power magnetic memory. Previous research has focused on spin-orbit torques generated by heavy metals[2-8], interfaces with strong Rashba interactions[9,10] and topological insulators [11-14]. These families of materials can all be well-described using models with noninteracting-electron bandstructures. Here, we show that electronic interactions within a strongly correlated heavy fermion material, the Kondo lattice system YbAl$_{3}$, can provide a large enhancement in spin-orbit torque. The spin-torque conductivity increases by approximately a factor of 4 as a function of decreasing temperature from room temperature to the coherence temperature of YbAl$_{3}$ ($T^* \approx 37$ K), with a saturation at lower temperatures, achieving a maximum value greater than any heavy metal element. This temperature dependence mimics the increase and saturation at $T^*$ of the density of states at the Fermi level arising from the ytterbium 4$f$-derived heavy bands in the Kondo regime, as measured by angle-resolved photoemission spectroscopy[15]. We therefore identify the many-body Kondo resonance as the source of the large enhancement of spin-orbit torque in YbAl$_{3}$. Our observation reveals new opportunities in spin-orbit torque manipulation of magnetic memories by engineering quantum many-body states.
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。
