Ground state of the organic spin-liquid material EtMe_3P[Pd(dmit)_2]_2
Ground state of the organic spin-liquid material EtMe_3P[Pd(dmit)_2]_2
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有机自旋液体材料EtMe_3P[Pd(dmit)_2]_2的基态
DOI：
10.1088/1742-6596/320/1/012033
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
S. Maegawa and R. Kato
中科院分区：
文献类型：
--
作者：
T. Itou;A. Oyamada;S. Maegawa and R. Kato
有机莫特绝缘体etme3sb [Pd (dmit) 2] 2是一个近正三角晶格上的1/2自旋体系。尽管存在强的反铁磁交换相互作用J= 220 ~ 250k，但它不表现出经典的反铁磁有序，因此可以认为它是一种自旋液体材料。我们发现自旋液态的(t1 T)−1在1k左右出现峰值，之后冷却时(t1 T)−1减小。这不是由于自旋动力学的减慢，因为t2−1在低温极限下没有表现出任何增强。因此，(t1 T)−1的减小归因于自旋激发的消失，这表明磁激发至少在q空间的某些部分获得了能隙。这表明，目前的自旋液体材料的基态不是具有自旋子费米表面的状态，在这种状态下，磁激发是完全无间隙的，因此(t1 T)−1不会降低到低温极限。
The organic Mott insulator EtMe 3 Sb [Pd (dmit) 2] 2 is a 1/2-spin system on a nearly-regular triangular lattice. It does not show classical antiferromagnetic ordering in spite of strong antiferromagnetic exchange interactions J= 220–250 K, and thus it is regarded as a spin liquid material. We have found that (T 1 T)− 1 of this spin liquid state shows a peak at around 1 K and after that (T 1 T)− 1 decreases on cooling. This is not attributed to slowing down of the spin dynamics because T 2− 1 does not show any enhancement down to low temperature limit. Therefore, the decrease of (T 1 T)− 1 is attributed to disappearance of spin excitations, suggesting that magnetic excitations acquire an energy gap at least in some portion of q-space. This indicates that the ground state of the present spin-liquid material is not a state with spinon Fermi surface, where magnetic excitations are fully gapless and thus (T 1 T)− 1 does not decrease down to low temperature limit.