CHINESE JOURNAL OF COMPUTATIONAL PHYSICS ›› 2018, Vol. 35 ›› Issue (2): 235-241.DOI: 10.19596/j.cnki.1001-246x.7602

Previous Articles     Next Articles

Influence of Contact Geometry on Electrical Transport Properties of Si4 Cluster: First Principles Study

LIU Futi1, ZHANG Shuhua2, CHENG Xiaohong1   

  1. 1. College of Physics and Electronic Engineering, Yibin University, Yibin 644000, China;
    2. College of Chemistry and Chemical Engineering, Yibin University, Yibin 644000, China
  • Received:2016-12-13 Revised:2017-02-25 Online:2018-03-25 Published:2018-03-25

Abstract: Influence of contact geometry including coupling morphology and distances on electrical transport properties of Si4 cluster coupled to two atomic Au(100)-3×3 electrodes is investigated from first principles with a combination of density functional theory and non-equilibrium Green's function method. Following situations of coupling morphology are considered:Si4 cluster is sandwiched between two atomic Au electrodes at top to top, top to hollow, hollow to hollow position. We optimize geometry of junctions at different distances. We calculate cohesion energy and conductance of junctions as a function of distance dz, and simulate Au-Si4-Au junctions breaking process. We obtain equilibrium conductances of the most stable structures for different coupling morphology. They are 0.71 G0, 0.96 G0, 2.44 G0, respectively. All junctions at stable structure have great conductance. In the range of voltage from -1.2 V to 1.2 V, I-V curve of junctions in the most stable structure shows linear characteristics. It shows that conductance is sensitive to coupling morphology and contact distance.

Key words: Si4 cluster, coupling morphology, nanoscale junctions, electrical transport

CLC Number: