标题： 通过在TiSe$_2$/TiO$_2$异质结构上基底诱导掺杂抑制电荷密度波 显示英文标题

标题： Suppression of Charge Density Wave by Substrate Induced Doping on TiSe$_2$/TiO$_2$ Heterostructure

摘要： 衬底工程为调节薄膜形式量子材料的物理性质提供了机会。 这里我们报告，在TiO$_2$上生长的TiSe$_2$薄膜表现出意外的高电子掺杂，这抑制了电荷密度波（CDW）序。 这与块体单晶TiSe$_2$或在石墨烯上的TiSe$_2$薄膜显著不同。 通过分子束外延（MBE）可以在TiO$_2$上以两种方式制备外延的TiSe$_2$薄膜：通过使用硒和钛源的常规共沉积，以及通过在重构的TiO$_2$表面上仅蒸发硒。 这两种生长方法都能产生原子级平坦且具有相似物理性质的薄薄膜。 电子掺杂和随后的CDW序抑制可以通过TiSe$_2$薄膜中的硒空位来解释，当使用TiO$_2$基底时，这些空位自然出现。 这是由于更强的界面键合改变了理想的生长条件。 我们的发现提供了一种通过基底选择和工程来调节硫属化物薄膜的化学势的方法。 显示英文摘要

摘要： Substrate engineering provides an opportunity to modulate the physical properties of quantum materials in thin film form. Here we report that TiSe$_2$ thin films grown on TiO$_2$ have unexpectedly large electron doping that suppresses the charge density wave (CDW) order. This is dramatically different from either bulk single crystal TiSe$_2$ or TiSe$_2$ thin films on graphene. The epitaxial TiSe$_2$ thin films can be prepared on TiO$_2$ via molecular beam epitaxy (MBE) in two ways: by conventional co-deposition using selenium and titanium sources, and by evaporating only selenium on reconstructed TiO$_2$ surfaces. Both growth methods yield atomically flat thin films with similar physical properties. The electron doping and subsequent suppression of CDW order can be explained by selenium vacancies in the TiSe$_2$ film, which naturally occur when TiO$_2$ substrates are used. This is due to the stronger interfacial bonding that changes the ideal growth conditions. Our finding provides a way to tune the chemical potential of chalcogenide thin films via substrate selection and engineering.