Universal low-temperature behavior of frustrated quantum antiferromagnets in the vicinity of the saturation field
Universal low-temperature behavior
of frustrated quantum antiferromagnets
in the vicinity of the saturation field
复制标题
饱和场附近受挫量子反铁磁体的普遍低温行为
DOI：
10.1140/epjb/e2006-00273-y
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Richter
中科院分区：
文献类型：
--
作者：
O. Derzhko;J. Richter
抽象的。
我们研究低温热力学性质
一些受挫的量子反铁磁体
支持局部磁振子态
在饱和场附近。
为此，我们使用
(1) 自旋系统低能自由度的映射
到硬核物体晶格气体上
和
(2) 有限自旋系统的精确对角化
最多 N=30 个站点。
所考虑的自旋系统表现出普遍的行为
这是由特定的硬核物体晶格气体决定的
代表独立的本地磁振子状态。
我们测试晶格气体描述
通过比较其预测
与数值结果
用于有限自旋系统的低能态。
对于所有考虑的受挫旋转系统，我们发现一个很大的变化
通过饱和场的低温比热和
饱和场处等温熵的最大值导致
增强磁热效应。
Abstract.
We study the low-temperature thermodynamic properties
of a number of frustrated quantum antiferromagnets
which support localized magnon states
in the vicinity of the saturation field.
For this purpose we use
(1) a mapping of the low-energy degrees of freedom of spin systems
onto the hard-core object lattice gases
and
(2) an exact diagonalization of finite spin systems
of up to N=30 sites.
The considered spin systems exhibit universal behavior
which is determined by a specific hard-core object lattice gas
representing the independent localized magnon states.
We test the lattice gas description
by comparing its predictions
with the numerical results
for low-lying energy states of finite spin systems.
For all frustrated spin systems considered we find a strong variation
of the low-temperature specific heat passing the saturation field and a
maximum in the isothermal entropy at saturation field resulting in an
enhanced magnetocaloric effect.