自旋-声子耦合对正方晶格自旋-1/2反铁磁体的影响

Effect of Spin Phonon Coupling on Spin 1/2 Heisenberg Antiferromagnet on a Square Lattice

在准自旋波理论框架内，应用正则变换方法讨论了有限温度下自旋－声子耦合相互作用对正方晶格自旋－１／２海森堡反铁磁体的影响．计算了系统的自旋－自旋关联函数．采用非绝热近似方法处理自旋－声子耦合相互作用．结果表明，通常的绝热近似处理方法所得的结果仅是此处结果的一种极限（ωｐｈ→０）情况．自旋－声子耦合相互作用可以削弱系统的拓扑长程序．

At finite temperatures, the effect of spin phonon coupling on spin 1/2 Heisenberg antiferromagnet on a square lattice was investigated by a unitary transformation approach within framework of the modified spin wave theory. The spin spin correlation function was calculated. A nonadiabatic approximation method was employed to deal with the spin phonon interaction. The calculations show that the results obtained by ordinary adiabatic approximation method is only the special results of that by the nonadiabatic method at the limit, ω ph →0. The topological long range order of the system can be reduced by spin phonon coupling. Thus, some kind of quantum spin liquid phase may be developed in the strong spin phonon coupled system.