Unconventional Field-Induced Spin Gap in an S=1/2 Chiral Staggered Chain
Unconventional Field-Induced Spin Gap in an S=1/2 Chiral Staggered Chain
复制标题
S=1/2 手性交错链中非常规场致自旋间隙
DOI：
10.1103/physrevlett.122.057207
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发表时间：
2019
影响因子：
8.6
通讯作者：
Williams, B. H.
中科院分区：
文献类型：
--
作者：
Liu, J.;Kittaka, S.;Johnson, R. D.;Lancaster, T.;Singleton, J.;Sakakibara, T.;Kohama, Y.;van Tol, J.;Ardavan, A.;Williams, B. H.
我们研究了分子基手性自旋链的低温磁性。电子自旋共振、磁力测量和热容量测量揭示了交错张量的存在、丰富的低温激发谱、交错的磁化率以及在施加磁场时打开的自旋间隙。这些现象让人想起以前在非手性交错链中观察到的那些现象，这些现象可以在sine-Gordon量子场理论中解释。然而，在目前的情况下，虽然sine-Gordon模型很好地解释了热容的温度依赖性，但差距的大小及其测量的线性场依赖性与sine-Gordon理论并不符合。我们建议，出现的差异是由于额外的条款，在哈密顿产生的手征结构，特别是一个统一的Dzyaloshinskiii-Moriya耦合和一个四重周期交错场。
We investigate the low-temperature magnetic properties of the molecule-based chiral spin chain(). Electron-spin resonance, magnetometry and heat capacity measurements reveal the presence of staggeredtensors, a rich low-temperature excitation spectrum, a staggered susceptibility, and a spin gap that opens on the application of a magnetic field. These phenomena are reminiscent of those previously observed in nonchiral staggered chains, which are explicable within the sine-Gordon quantum-field theory. In the present case, however, although the sine-Gordon model accounts well for the form of the temperature dependence of the heat capacity, the size of the gap and its measured linear field dependence do not fit with the sine-Gordon theory as it stands. We propose that the differences arise due to additional terms in the Hamiltonian resulting from the chiral structure of, particularly a uniform Dzyaloshinskii-Moriya coupling and a fourfold periodic staggered field.