Electrostatic potential screened by a two-dimensional electron system: A real-space observation by scanning-tunneling spectroscopy
Electrostatic potential screened by a two-dimensional electron system: A real-space observation by scanning-tunneling spectroscopy
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DOI：
10.1103/physrevlett.96.016801
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发表时间：
2006-01-13
影响因子：
8.6
通讯作者：
Hasegawa, Y
中科院分区：
文献类型：
--
作者：
Ono, M;Nishigata, Y;Hasegawa, Y
利用扫描隧道光谱技术研究了Si（111）-root 3xroot 3Ag表面亚纳米空间分辨率的静电势分布。从表面上的电子状态的能级位移测量的电位。得到的潜在的图像显示，周围的步骤和Ag吸附的电位下降，据推测，正电荷积累。用表面二维电子气（2DEG）对电荷的屏蔽作用解释了还原电位的分布。弗里德尔振荡，这是从筛选结果，并有一个周期的半费米波长的2DEG，也被观察到的潜在的图像。
Scanning-tunneling spectroscopy at 5 K was used to investigate the electrostatic potential profile on the Si(111)-root 3x root 3 Ag surface at subnanometer spatial resolution. The potential was measured from an energy-level shift of electronic states on the surface. The potential images obtained reveal that the potential drops around the steps and Ag adsorbates, upon which positive charges are presumably accumulated. The profiles of the reduced potentials are explained with the screening of potential due to the charges by two-dimensional electron gas (2DEG) existing on the surface. The Friedel oscillation, which results from the screening and has a period of the half Fermi wavelength of the 2DEG, was also observed in the potential images.