交错磁场下二维三角晶格中的拓扑量子相变  

Staggered flux driven topological quantum phase transition on two-dimensional tight-binding electron system

作　　者：严密[1] 

机构地区：[1]苏州大学物理科学与技术学院,江苏苏州215006

出　　处：《苏州大学学报（自然科学版）》2012年第3期51-56,共6页Journal of Soochow University(Natural Science Edition)

基　　金：国家自然科学基金(11074183)

摘　　要：详细研究了二维三角格子中的紧束缚电子在交错磁场驱动下的拓扑量子相变.总磁场由磁通为Ф的均匀磁场和磁通为ΔФ的交错磁场两部分构成.当均匀磁通Ф固定时,交错磁通强度的改变会导致量子Hall电导的跳变和邻近Landau子能带间Chern数的重新分配.这种相变在弱无序情况下仍然存在.通过计算系统的基态能,这种相变是三级相变.我们也研究基态保真度随交错磁通从0增大到ΔФc时的变化情况.A peculiar staggered-flux driven topological quantum phase transition on two-dimensional triangular lattice filled with tight-binding electrons is studied in detail.The total magnetic fields have a uniform flux with strength Ф and a staggered flux with strength ΔФ.When the uniform flux strength is fixed,the variation of staggered flux strength leads to the quantized Hall conductance exhibiting a direct transition and the redistribution of Chern number between neighboring Landau subbands.The phase transition is robust against weak disorder.The calculation of the total free energy of the system shows the phase transition is a 3rd order phase transition.Moreover,the ground state fidelity susceptibility when staggered flux increases from 0 to the critical value ΔФc is also investigated.

关 键 词：拓扑量子相变 紧束缚模型 三角晶格 交错磁通 

分 类 号：O46[理学—电子物理学]