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arXiv · 0803.0984

Conservation and persistence of spin currents and their relation to the Lieb-Schulz-Mattis twist operators

N. Bray-Ali·Z. Nussinov
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Abstract

Systems with spin-orbit coupling do not conserve "bare" spin current $\bf{j}$. A recent proposal for a conserved spin current $\bf{J}$ [J. Shi {\it et.al} Phys. Rev. Lett. {\bf 96}, 076604 (2006)] does not flow persistently in equilibrium. We suggest another conserved spin current $\bar{\bf{J}}$ that may flow persistently in equilibrium. We give two arguments for the instability of persistent current of the form $\bf{J}$: one based on the equations of motions and another based on a variational construction using Lieb-Schulz-Mattis twist operators. In the absence of spin-orbit coupling, the three forms of spin current coincide.

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N. Bray-Ali, Z. Nussinov. 2009-05-15. Conservation and persistence of spin currents and their relation to the Lieb-Schulz-Mattis twist operators. https://doi.org/10.1103/physrevb.80.012401

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