Open AccessGold nanowire tip-contact-related negative differential resistance twice and the rectification effects
Author(s) -
Yonghui Li,
Qiang Yan,
Zhou Li-ping,
Han Qin
Publication year - 2015
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.64.057301
Subject(s) - rectification , materials science , electrode , contact resistance , atomic orbital , condensed matter physics , electron , nanowire , density functional theory , fermi level , conductance , biasing , atom (system on chip) , molecular physics , atomic physics , physics , nanotechnology , voltage , layer (electronics) , quantum mechanics , computer science , embedded system
Electron transport properties of molecular junctions formed by 1, 4-dithiolbenzene(DTB) coupled to [1,1,1] Au nanowires are investigated by using the method of non-equilibrium Green's functions based on first-principle density functional theory. Different S-Au contact configurations are constructed and optimized. The junction with tip-type Au electrode top binding to a thio (S) atom is illustrated by the best configuration for electron transport. Juntions with asymmetric electrode-DTB contact show excellent rectifying performance (the largest rectification ratio being 25.6). Other junctions display negative differential resistance (NDR) effect twice. Analysis shows that the rectifying effect may originate from the difference between the stabilities of S-Au contact modes at both sides. Molecular orbitals including the tip Au atoms are calculated. In low bias region, the orbitals near the Fermi energy dominate the electrons transmission; while, as the bias increases, those apart from the Fermi energy contribute to the transport, along with the DTB eigen-level. During the whole process, the locations and amplitude of transmission vary with bias voltage and I/V curves show two peaks, resulting in twice-NDR effect.