QUANTUM CHEMICAL MODELING OF THE SCANNING TUNNELING MICROSCOPE

被引:8
作者
BADZIAG, P [1 ]
VERWOERD, WS [1 ]
机构
[1] UNIV S AFRICA,DEPT PHYS,POB 392,PRETORIA 0001,SOUTH AFRICA
关键词
D O I
10.1016/0039-6028(93)90426-K
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
An approach to the calculation of the tunneling current in STS and STM experiments from the results of quantum chemical atomic cluster calculations, is presented. Essential features of the model are that the final states involved in the expression derived by Tersoff and Hamann, are excited states rather than ionised states, and furthermore these states have to be calculated from multiconfiguration CI wavefunctions. The method is applied to measurements on the clean and hydrogenated Si(100) surface. Good agreement with measured STS curves is obtained, but only when the dimer geometry is allowed to respond to the biasing voltage to give a zero buckling of the dimer when a positive bias voltage is applied to the surface, and a buckling of 0.41 angstrom for a negative bias. For the hydrogenated surface the tunneling is found to drastically weaken the dimer bond. Good qualitative agreement is also found for calculated and measured topography curves for an STM tip scanning over the dimer in the dimer plane.
引用
收藏
页码:145 / 156
页数:12
相关论文
共 25 条
[21]   THE ASYMMETRIC DIMER ON SI(100) - CORRELATION-EFFECTS IN CLUSTER CALCULATIONS [J].
VERWOERD, WS .
SURFACE SCIENCE, 1983, 129 (2-3) :419-431
[22]  
VERWOERD WS, 1981, SURF SCI, V99, P581
[23]   ELECTRONIC STATES OF ASYMMETRIC DIMERS AT THE SI(100)-(2 X-1) SURFACE IN ELECTRIC-FIELDS [J].
WATANABE, K ;
WATANABE, K .
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 1992, 61 (02) :419-422
[24]   ATOMIC-STRUCTURE OF SI[001]2X1 [J].
YANG, WS ;
JONA, F ;
MARCUS, PM .
PHYSICAL REVIEW B, 1983, 28 (04) :2049-2059
[25]   THE 2 X 1 STRUCTURAL RECONSTRUCTION OF SI(001) [J].
YANG, WS ;
JONA, F ;
MARCUS, PM .
SOLID STATE COMMUNICATIONS, 1982, 43 (11) :847-851