摘要
采用双时格林函数方法研究了自旋为1的双层平方晶格阻挫模型的相变行为.详细探讨了层间耦合相互作用J_(c)和单离子各向异性参数D对奈尔态(AF1)和共线态(AF2)之间相转换的影响.结果显示:只要参数J_(c)和D不同时为零,奈尔态和共线态在J_(2)=J_(1)/2(这里J_(1)和J_(2)分别描述的是系统自旋间最近邻和次近邻交换作用)时的相变温度相等,两个态共存.在低于相变点的温度范围内,AF1-AF2态之间可以发生相转换,其相变类型为一阶相变.当J_(2)≠J_(1)/2时,尽管AF1-AF2态有不同相变温度,但它们也可以共存.如果AF1(AF2)态的相变温度大,在低温,AF1(AF2)态更稳定;在高温,AF2(AF1)态更稳定;在中间温度范围内,AF1-AF2态之间也可以发生一阶相转换.
In this paper,we investigate the phase transition of the spin-1 frustrated model on a square-lattice bilayer by the double-time Green’s function method.The effects of the interlayer coupling parameter J_(c) and single-ion anisotropy D on phase transformation between the Nèel state(AF1)and collinear state(AF2)are explored.Our results show that if only the parameters J_(c) and D are not equal to zero at the same time,the two states can exist and have the same critical temperature at J_(2)=J_(1)/2,which represents the nearest neighbor exchange.Under such parameters,a first-order phase transformation between these two states below the critical point can occur.For J_(2)≠J_(1)/2,although both states may exist,their Neel temperatures differ from each other.If the Nèel point of the AF1(AF2)state is larger,then at very low temperature,the AF1(AF2)state is more stable.Thus,in an intermediate temperature,a first-order phase transition between these two states may also occur.
作者
卿煜林
彭小莉
胡爱元
Qing Yu-Lin;Peng Xiao-Li;Hu Ai-Yuan(College of Physics and Electronic Engineering,Chongqing Normal University,Chongqing 401331,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第4期220-228,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11875010,12175027)
重庆市自然科学基金(批准号:cstc2021jcyj-msxmX0168,cstc2019jcyj-msxmX0217,cstc2019jcyj-msxmX0251)资助的课题。
关键词
反铁磁
磁各向异性
磁序的一般理论和模型
交换和超交换相互作用
antiferromagnetic
magnetic anisotropy
general theory and models of magnetic ordering
exchange and superexchange interactions
作者简介
通信作者:胡爱元,huaiyuan@cqnu.edu.cn。
