论文标题
过渡金属二分法中电荷密度波的相变的原子间潜在理论
Interatomic potential theory on the phase transition of charge density wave in transition metal dichalcogenides
论文作者
论文摘要
过渡金属二分法中的模式和电荷密度波（CDW）表现出取决于压力，温度，金属插入或chalcogen合金的复杂相图。在现象学兰道自由能模型的背景下，相图已被理解，但是它们的微观机制仍然不清楚。在这里，我们提出了一种基于原子间电位的新的微观理论，并使用从第一原理计算中提取的原子势已经明确计算了温度依赖性相图。通过详细的原子结构，单层H-Tase2的计算相图成功地再现了实验特征，例如相应的锁定和条纹阶段。我们的工作表明，电荷密度波的复杂行为起源于原子间潜能的相对简单结构，并阐明了晶格非骚扰性在CDW相变的作用。
Patterns and periods of charge density waves (CDW) in transition metal dichalcogenides exhibit complex phase diagrams that depend on pressure, temperature, metal intercalation, or chalcogen alloying. The phase diagrams have been understood in the context of phenomenological Landau free energy model, but the microscopic mechanisms underlying them are still not clear. Here, we present a new microscopic theory based on the interatomic potential, and have explicitly calculated temperature-dependent phase diagrams using the interatomic potential extracted from first-principles calculations. With detailed atomic structures, the calculated phase diagram of monolayer H-TaSe2 successfully reproduces the experimental features such as commensurate lock-in and stripe phase. Our work shows the complex behaviors of charge density wave are originated from the relatively simple structure of the interatomic potential and elucidates the role of lattice anharmonicity on the CDW phase transition.
