论文标题
2D Su-Schrieffer-Heeger模型的量子蒙特卡洛模拟
Quantum Monte Carlo Simulations of the 2D Su-Schrieffer-Heeger Model
论文作者
论文摘要
在过去的几年中，新一代的量子模拟大大扩展了我们对汉密尔顿人电荷密度波相变的理解，而局部声子模式与现场电荷密度之间的耦合。一个完全不同且有趣的案例是声子生活在键上的情况，因此调节电子跳跃。迄今为止，这种情况是由Su-Schrieffer-Heeger（SSH）Hamiltonian描述的，仅在一个维度上与量子蒙特卡洛进行了研究。在这里，我们介绍了2D SSH模型的结果，并表明在半填充时存在键有序的波（BOW）绝缘子，并认为具有电子偶联的临界值是其发作所需的，与任何非零耦合的弓都存在的1D情况相反。我们确定了迄今为止存在争议的键排序模式的确切性质，以及与$ {\ cal z} _4 $对称性的自发断裂有关的临界过渡温度。
Over the last several years, a new generation of quantum simulations has greatly expanded our understanding of charge density wave phase transitions in Hamiltonians with coupling between local phonon modes and the on-site charge density. A quite different, and interesting, case is one in which the phonons live on the bonds, and hence modulate the electron hopping. This situation, described by the Su-Schrieffer-Heeger (SSH) Hamiltonian, has so far only been studied with quantum Monte Carlo in one dimension. Here we present results for the 2D SSH model, and show that a bond ordered wave (BOW) insulator is present in the ground state at half-filling, and argue that a critical value of the electron-phonon coupling is required for its onset, in contradistinction with the 1D case where BOW exists for any nonzero coupling. We determine the precise nature of the bond ordering pattern, which has hitherto been controversial, and the critical transition temperature, which is associated with a spontaneous breaking of ${\cal Z}_4$ symmetry.
