论文标题
Berezinskii-Kosterlitz-二维铁电的阶段
Berezinskii-Kosterlitz-Thouless Phase in Two-dimensional Ferroelectrics
论文作者
论文摘要
著名的Berezinskii-Kosterlitz-Thouless（BKT）相过渡是指通过在二维（2D）系统中解离涡流 - 抗逆转器对的拓扑过渡。这种不寻常的阶段已经在各种类型的材料中报道，但在新的单位厚度（1UC）铁电元（也是2D铁电原理）中制造的新型系统中。在这里，使用基于第一原理的有效哈密顿方法导致发现了1uc Tin Tellurium完全放松的铁电和副态之间存在的BKT阶段的许多指纹。此外，发现外延菌株对1UC SNTE的这种BKT相的温度范围产生巨大后果。因此，我们的预测将BKT理论的操场扩展到了新型的功能材料，并证明应变是改变那里BKT特征的有效工具。
The celebrated Berezinskii-Kosterlitz-Thouless (BKT) phase transition refers to a topological transition characterized, e.g., by the dissociation of vortex-antivortex pairs in two-dimensional (2D) systems. Such unusual phase has been reported in various types of materials, but never in the new class of systems made by one-unit-cell-thick (1UC) ferroelectrics (also coined as 2D ferroelectrics). Here, the use of a first-principles-based effective Hamiltonian method leads to the discovery of many fingerprints of a BKT phase existing in-between the ferroelectric and paraelectric states of 1UC tin tellurium being fully relaxed. Moreover, epitaxial strain is found to have dramatic consequences on the temperature range of such BKT phase for the 1UC SnTe. Consequently, our predictions extend the playground of BKT theory to a novel class of functional materials, and demonstrate that strain is an effective tool to alter BKT characteristics there.
