Universal intrinsic higher-rank spin tensor Hall effect
Universal intrinsic higher-rank spin tensor Hall effect
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DOI：
10.1103/physrevb.107.085410
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发表时间：
2023-02
影响因子：
3.7
通讯作者：
Ying Su;Junpeng Hou;Chuanwei Zhang
中科院分区：
文献类型：
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作者：
Ying Su;Junpeng Hou;Chuanwei Zhang
横向自旋电流不为零而电荷电流为零的自旋霍尔效应在自旋电子学中有重要的应用。由于电子的半自旋性质，自旋输运迄今仅限于秩1自旋矢量，而更高阶的自旋张量存在并在更大自旋（（cid：2）1）系统中起重要作用。例如，在自旋为1的系统中，有五个线性独立的秩为2的自旋四极张量，表征自旋向列。虽然这些内部自旋张量自由度大大丰富了大自旋超冷气体的量子相位和动力学，但自旋张量的量子输运仍然在很大程度上未被探索。本文研究了高阶自旋张量流，并引入了大自旋系统中自旋张量霍尔效应的概念。我们发现，一个净横向自旋张量电流可以由一个外场在纵向驱动，而不存在低阶自旋或电荷电流。重要的是，我们在具有内禀自旋轨道耦合的自旋1模型中确定了普遍的秩2自旋张量霍尔电导率q / 8 π（带有载流子电荷q），这与详细的模型参数无关。STHE需要违反时间反演对称性（TRS），但可以通过与秩2自旋张量相关的唯一伪TRS来保护。提出了一种利用赝自旋1超冷费米子原子，通过自旋张量积累实现和探测超自旋量子阱的实验方案。利用SU（2）子代数和SU（N）群的广义Gell-Mann矩阵表示，给出了大自旋STHE推广的一般途径.我们的工作揭示了一种内禀自旋张量输运现象，并为霍尔效应家族引入了一个新成员，
The spin Hall effect with nonzero transverse spin current but vanishing charge current has important applications in spintronics. Owing to the half-spin nature of electrons, the spin transport has hitherto been restricted to the rank-1 spin vector, whereas higher-rank spin tensors exist and play important roles in larger-spin ( (cid:2) 1) systems. For instance, there are five linearly independent rank-2 spin quadrupole tensors, characterizing the spin nematics, in a spin-1 system. While these internal spin-tensor degrees of freedom substantially enrich the quantum phases and dynamics of large-spin ultracold gases, the quantum transport of spin tensors remains largely unexplored yet. Here we investigate the higher-rank spin tensor current and introduce the concept of the spin tensor Hall effect (STHE) in a large-spin system. We find that a net transverse spin tensor current can be driven by an external field in the longitudinal direction, while no lower-rank spin or charge current exists. Significantly, we identify a universal rank-2 spin tensor Hall conductivity q / 8 π (with the carrier charge q ) in a spin-1 model with intrinsic spin-orbit coupling, which is independent of the detailed model parameters. The STHE requires the violation of time-reversal symmetry (TRS) but can be protected by a unique pseudo-TRS associated with the rank-2 spin tensor. An experimental scheme is proposed to realize and detect the STHE with pseudospin-1 ultracold fermionic atoms and through the spin tensor accumulation. A general route towards the generalization of the STHE for larger spins is provided, using the SU(2) subalgebra and generalized Gell-Mann matrix representation of the SU( N ) group. Our work reveals an intrinsic spin tensor transport phenomenon and introduce a new member to the Hall effect families, which may pave