论文标题
量子Yu-Shiba-Rusinov二聚体
Quantum Yu-Shiba-Rusinov dimers
论文作者
论文摘要
超导底物上的磁化体发生量子相变，随着它们与传导电子的交换耦合增加。对于量子旋转，这种过渡伴随着筛选Adatom自旋。在这里，我们探讨了该筛选对磁性变化液的相图和子仪激发光谱的后果，并通过其Yu-Shiba-Rusinov状态和自旋旋转相互作用的杂交结合。我们专门考虑了更高的自旋，单离子各向异性，Ruderman-Kiter-kasuya-Yosida耦合以及与过渡金属和稀有地系统相关的Dzyaloshinsky-Moriya相互作用。我们基于零带宽近似的灵活方法提供了详细的物理洞察力，并且与可用的数值 - 纯正型组计算在单体和二聚体上具有出色的定性一致性。值得注意的是，我们发现，即使在大型杂质旋转或强烈的单离子各向异性的极限中，量子旋转二聚体的相图仍然与基于经典旋转的相图质量不同，突显了对量子Yu-shiba-rusinov二聚体理论的需求。
Magnetic adatoms on a superconducting substrate undergo a quantum phase transition as their exchange coupling to the conduction electrons increases. For quantum spins, this transition is accompanied by screening of the adatom spin. Here, we explore the consequences of this screening for the phase diagrams and subgap excitation spectra of dimers of magnetic adatoms coupled by hybridization of their Yu-Shiba-Rusinov states and spin-spin interactions. We specifically account for higher spins, single-ion anisotropy, Ruderman-Kittel-Kasuya-Yosida coupling, and Dzyaloshinsky-Moriya interactions relevant in transition-metal and rare-earth systems. Our flexible approach based on a zero-bandwidth approximation provides detailed physical insight and is in excellent qualitative agreement with available numerical-renormalization group calculations on monomers and dimers. Remarkably, we find that even in the limit of large impurity spins or strong single-ion anisotropy, the phase diagrams for dimers of quantum spins remain qualitatively distinct from phase diagrams based on classical spins, highlighting the need for a theory of quantum Yu-Shiba-Rusinov dimers.
