Collective spinon spin wave in a magnetized U(1) spin liquid
Collective spinon spin wave in a magnetized U(1) spin liquid
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DOI：
10.1103/physrevb.101.020401
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发表时间：
2019-04
影响因子：
3.7
通讯作者：
L. Balents;O. Starykh
中科院分区：
文献类型：
--
作者：
L. Balents;O. Starykh
研究了二维U(1)自旋费米面自旋液体在外加小塞曼场中的横向动力学自旋极化率。我们表明，存在于一般费米液体中的短程相互作用，以及U(1)自旋液体特有的规范涨落，都定性地改变了基于经常假设的无相互作用自旋近似的结果。这种相互作用的短程部分导致一个集体的“自旋自旋波”模，它以很小的动量从双自旋连续统中分裂出来，并向下扩散。规范涨落使磁化率重新正规化，在自旋连续体之外的区域提供了非零幂律权重，并赋予自旋波有限的寿命，其大小与动量平方成正比。我们还研究了Dzyaloshinskii-Moriya各向异性对零动量极化率的影响，用电子自旋共振(ESR)测量了零动量极化率，得到了共振线宽随温度线性变化，在低温下随磁场变化。我们的结果构成了非弹性中子散射、ESR和共振非弹性X射线散射的理论基础，研究了这种量子自旋-液体状态。
We study the transverse dynamical spin susceptibility of the two-dimensional U(1) spinon Fermi-surface spin liquid in a small applied Zeeman field. We show that both short-range interactions, present in a generic Fermi liquid, as well as gauge fluctuations, characteristic of the U(1) spin liquid, qualitatively change the result based on the frequently assumed noninteracting spinon approximation. The short-range part of the interaction lead to a collective ``spinon spin wave'' mode, which splits off from the two-spinon continuum at a small momentum and disperses downward. Gauge fluctuations renormalize the susceptibility, providing nonzero power-law weight in the region outside the spinon continuum and giving the spin wave a finite lifetime, which scales as momentum squared. We also study the effect of Dzyaloshinskii-Moriya anisotropy on the zero momentum susceptibility, which is measured in electron spin resonance (ESR), and obtain a resonance linewidth linear in temperature and varying as ${B}^{2/3}$ with magnetic field $B$ at low temperatures. Our results form the basis for a theory of inelastic neutron scattering, ESR, and resonant inelastic x-ray scattering studies of this quantum spin-liquid state.