论文标题
摩尔电势，晶格松弛和层次偏振的MOS2双层
Moire Potential, Lattice Relaxation and Layer Polarization in Marginally Twisted MoS2 Bilayers
论文作者
论文摘要
半导体过渡金属二进制元素（TMDS）的人为扭曲的异质结构通过空间调制层间相互作用和结构重建，从而对其电子和光学性质进行了前所未有的控制。在这里，我们使用扫描隧道显微镜/光谱研究在0°附近的扭曲角度研究扭曲的MOS2双层。我们研究了Moiré图案的扭曲角度依赖性，该图案由小角度（<2°）的晶格重建主导，导致大型三角形结构域具有菱形堆积。局部光谱测量结果显示，角度<3°的较大的Moiré电位强度为100-200 MEV。在重建的区域中，我们看到相邻三角形结构域之间的偏置依赖性不对称性，我们与垂直极化有关，该垂直极化与菱形堆积的TMD固有。这种观点是由光谱图和环境压电测量支持的。我们的结果为这类新的界面铁电界提供了微观的观点，并可以为设计实现这一效果的新型异质结构提供线索。
Artificially twisted heterostructures of semiconducting transition metal dichalcogenides (TMDs) offer unprecedented control over their electronic and optical properties via the spatial modulation of interlayer interactions and structural reconstruction. Here we study twisted MoS2 bilayers in a wide range of twist angles near 0° using Scanning Tunneling Microscopy/Spectroscopy. We investigate the twist angle-dependence of the moiré pattern which is dominated by lattice reconstruction for small angles (<2°) leading to large triangular domains with rhombohedral stacking. Local spectroscopy measurements reveal a large moiré-potential strength of 100-200 meV for angles <3°. In reconstructed regions we see a bias-dependent asymmetry between neighboring triangular domains which we relate to the vertical polarization which is intrinsic to rhombohedral stacked TMDs. This viewpoint is urther supported by spectroscopy maps and ambient Piezoresponse measurements. Our results provide a microscopic perspective on this new class of interfacial ferroelectrics and can offer clues for designing novel heterostructures which harness this effect.
