论文标题
在极地表面出现的电子状态竞争
Competing electronic states emerging on polar surfaces
论文作者
论文摘要
离子化合物的极性表面上的过量电荷通常由二维电子气体（2DEG）模型（一种均匀的电荷分布）描述，该模型是在几个原子层中空间限制的。在这里，通过将扫描探针显微镜与密度功能理论计算相结合，我们表明，对极性TAO $ _2 $ termination of Ktao $ _3 $（001）的过量充电形成了更复杂的电子状态，具有不同程度的空间和电子定位：电荷密度波（电荷密度波（CDW）与强度元素化的电子极性和BIPALARONS和BIPALARONS，BIPARONS和BIPALARONS。这些表面电子重建源自电子晶体相互作用和电子相关的联合作用，在能量上比2DEG溶液更有利。它们表现出明显的光谱信号，并对表面特性产生影响，这表现为铁电畸变的局部抑制。控制收费程度和从铁电到副态的过渡对于电子应用中载体的产生和运输可能会有很大的好处。
Excess charge on polar surfaces of ionic compounds is commonly described by the two-dimensional electron gas (2DEG) model, a homogeneous distribution of charge, spatially-confined in a few atomic layers. Here, by combining scanning probe microscopy with density functional theory calculations, we show that excess charge on the polar TaO$_2$ termination of KTaO$_3$(001) forms more complex electronic states with different degrees of spatial and electronic localization: charge density waves (CDW) coexist with strongly-localized electron polarons and bipolarons. These surface electronic reconstructions, originating from the combined action of electron-lattice interaction and electronic correlation, are energetically more favorable than the 2DEG solution. They exhibit distinct spectroscopy signals and impact on the surface properties, as manifested by a local suppression of ferroelectric distortions. Controlling the degree of charge ordering and the transition from ferroelectric to paraelectric states could be of great benefit for the generation and transport of carriers in electronic applications.
