论文标题
使用Van Hove Singularity在2H-Tase $ _ {2} $中控制电荷密度订单
Controlling charge density order in 2H-TaSe$_{2}$ using a van Hove singularity
论文作者
论文摘要
我们报告了van霍夫奇异性与2H-Tase $ _ {2} $中的电荷密度波状态之间的相互作用。我们使用角度分辨光发射光谱来研究该材料表面的费米表面的变化，并用钾掺杂。在高掺杂时，我们观察到修改，这意味着$（3 \ times 3）$电荷密度波和不同相关状态的形成的消失。使用基于紧密的方法以及有效的模型，我们解释了我们的观察结果，这是由于单粒子Lifshitz过渡之间的耦合而导致的，在此期间，费米水平通过Van Hove的奇异性和电荷密度顺序。在这种情况下，与Van Hove奇点相关的高电子密度会导致电荷密度波的周期性从已知的$（3 \ times 3）$转变为新的$（2 \ times 2）$ superlattice。
We report on the interplay between a van Hove singularity and a charge density wave state in 2H-TaSe$_{2}$. We use angle-resolved photoemission spectroscopy to investigate changes in the Fermi surface of this material under surface doping with potassium. At high doping, we observe modifications which imply the disappearance of the $(3\times 3)$ charge density wave and formation of a different correlated state. Using a tight-binding-based approach as well as an effective model, we explain our observations as a consequence of coupling between the single-particle Lifshitz transition during which the Fermi level passes a van Hove singularity and the charge density order. In this scenario, the high electronic density of states associated with the van Hove singularity induces a change in the periodicity of the charge density wave from the known $(3\times 3)$ to a new $(2\times 2)$ superlattice.
