Quantum stabilization of classically unstable plateau structures
Quantum stabilization of classically unstable plateau structures
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DOI：
10.1103/physrevb.87.060407
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发表时间：
2013-02-19
影响因子：
3.7
通讯作者：
Mila, Frederic
中科院分区：
文献类型：
--
作者：
Coletta, Tommaso;Zhitomirsky, M. E.;Mila, Frederic
一个有趣的报告的动机，在一些挫折的量子反铁磁体，磁化高原的简单共线结构是不稳定的外部磁场在经典极限，我们开发了一个半经典的方法来估计零点能量的共线配置，即使它们不对应于一个局部最小的经典能量。对于自旋为1/2的阻挫正方晶格反铁磁体，当J（2）/J（1）> 1/2时，这种方法导致了一个大的1/2平台的稳定，具有“上-上-上-下”结构，与精确对角化结果一致，而对于自旋为1/2的各向异性三角形反铁磁体，预测了具有“up-up-down”结构的1/3平台在远离各向同性点处是稳定的，与Cs_2CuBr_4的性质一致。DOI：10.1103/PhysRevB.87.060407
Motivated by an intriguing report, in some frustrated quantum antiferromagnets, of magnetization plateaus whose simple collinear structure is not stabilized by an external magnetic field in the classical limit, we develop a semiclassical method to estimate the zero-point energy of collinear configurations even when they do not correspond to a local minimum of the classical energy. For the spin-1/2 frustrated square-lattice antiferromagnet, this approach leads to the stabilization of a large 1/2 plateau with "up-up-up-down" structure for J(2)/J(1) > 1/2, in agreement with exact diagonalization results, while for the spin-1/2 anisotropic triangular antiferromagnet, it predicts that the 1/3 plateau with "up-up-down" structure is stable far from the isotropic point, in agreement with the properties of Cs2CuBr4. DOI: 10.1103/PhysRevB.87.060407