Spin transport in a quantum spin orbital liquid
Spin transport in a quantum spin orbital liquid
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DOI：
10.1103/physrevb.104.l060403
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发表时间：
2021-04
影响因子：
3.7
通讯作者：
Zekun Zhuang;J. Marston
中科院分区：
文献类型：
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作者：
Zekun Zhuang;J. Marston
量子自旋轨道液体（QSOL）是一种新的物质相，类似于量子自旋液体，在自旋和轨道自由度上都有量子涨落。利用非平衡绿色函数理论研究了Yao和Lee提出的一个精确可解的QSOL模型中的非平衡自旋输运。我们发现，自旋输运问题可以映射到一个自由费米子的问题与有效的费米子浴，具有迅速变化的状态密度。在无间隙阶段，自旋电流$I_s-V_s$关系因此是高度非线性的，而在手性间隙阶段，自旋电流电导被量子化为1/2\pi$，前提是接触足够宽。量子化的电导是一个签名的拓扑性质的手征能隙的QSOL。
Quantum spin-orbital liquids (QSOLs) are a novel phase of matter, similar to quantum spin liquids, with quantum fluctuations in both spin and orbital degrees of freedom. We use non-equilibrium Green's function theory to study out-of-equilibrium spin transport in an exactly solvable QSOL model put forward by Yao and Lee. We find that the spin transport problem can be mapped to that of a free fermion problem with effective fermionic baths that have rapidly varying density of states. In the gapless phase, the spin current $I_s-V_s$ relation is thus highly nonlinear, while in the chiral gapped phase, the spin current conductance is quantized to be $1/2\pi$ provided that the contacts are sufficiently wide. The quantized conductance is a signature of the topological nature of the chiral gapped QSOL.