论文标题
yu-shiba-rusinov在$ s-wave $超导体中的单磁分子状态
Yu-Shiba-Rusinov states of single magnetic molecule in an $s-wave$ superconductor
论文作者
论文摘要
我们使用数值重归其化群体理论来研究位于S波超导底物中的单个磁分子的Yu-Shiba-Rusinov（YSR）结合状态性质。该分子由大核自旋和单轨道组成，并通过交换相互作用结合。在这种交换相互作用的存在下，对于铁运动和抗铁磁耦合，单线/双重跃迁的临界库仑相互作用降低。 YSR状态的数量也增加到两对，但是，在单线阶段，其中一个对具有零光谱的重量。我们使用安德森模型探讨了间隙状态的演变。远离粒子 - 孔对称点，结果表明，随着现场能量的降低，在保持库仑相互作用固定的同时，双线线双线横梁过渡。为了理解这些结果，我们在大型超导顺序参数的极限下写下了一个有效的分子模型。从定性上讲，它解释了距离状态的各种相变和光谱性质。最后，我们分析了核心自旋对缝隙状态的磁各向异性场的影响。由于旋转激发态的内部自由度，差距内出现了许多新状态。根据单轴各向异性场的符号和强度，结果表明多达三对YSR状态。
We use the numerical renormalization group theory to investigate the Yu-Shiba-Rusinov (YSR) bound state properties of single magnetic molecules placed in an s-wave superconducting substrate. The molecule consist of a large core spin and a single orbital, coupled via an exchange interaction. The critical Coulomb interaction for the singlet/doublet transition decreases in the presence of this exchange interaction for both ferro and anti-ferromagnetic couplings. The number of YSR states also increase to two pairs, however, in the singlet phase, one of the pairs have zero spectral weight. We explore the evolution of the in-gap states using the Anderson model. Away from the particle-hole symmetry point, the results suggest a doublet-singlet-doublet transition as the on-site energy is lowered while keeping the Coulomb interaction fixed. To understand these results, we write down an effective model for the molecule in the limit of large superconducting order parameter. Qualitatively, it explains the various phase transitions and spectral nature of the in-gap states. Finally, we analyze the effects of magnetic anisotropic fields of the core spin on in-gap states. Due to internal degrees of freedom of the spin excited states, a multitude of new states emerges within the gap. Depending on the sign and strength of the uniaxial anisotropic field, the results indicate up to three pairs of YSR states.
