Imperial College London
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ProfessorAndrewHorsfield

Faculty of Engineering, Department of Materials

Professor of Theory and Simulation of Materials
 
 
 
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Contact

 

+44 (0)20 7594 6753a.horsfield

 
 
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Location

 

Bessemer B331Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Horsfield:2016:10.1103/PhysRevB.94.075118,
author = {Horsfield, AP and Boleininger, M and D'Agosta, R and Iyer, V and Thong, A and Todorov, T and White, C},
doi = {10.1103/PhysRevB.94.075118},
journal = {Physical Review B},
title = {Efficient simulations with electronic open boundaries},
url = {http://dx.doi.org/10.1103/PhysRevB.94.075118},
volume = {94},
year = {2016}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We present a reformulation of the Hairy Probe method for introducing electronic open boundariesthat is appropriate for steady state calculations involving non-orthogonal atomic basis sets. As acheck on the correctness of the method we investigate a perfect atomic wire of Cu atoms, and aperfect non-orthogonal chain of H atoms. For both atom chains we find that the conductance hasa value of exactly one quantum unit, and that this is rather insensitive to the strength of couplingof the probes to the system, provided values of the coupling are of the same order as the meaninter-level spacing of the system without probes. For the Cu atom chain we find in addition thataway from the regions with probes attached, the potential in the wire is uniform, while withinthem it follows a predicted exponential variation with position. We then apply the method to aninitial investigation of the suitability of graphene as a contact material for molecular electronics.We perform calculations on a carbon nanoribbon to determine the correct coupling strength of theprobes to the graphene, and obtain a conductance of about two quantum units corresponding totwo bands crossing the Fermi surface. We then compute the current through a benzene moleculeattached to two graphene contacts and find only a very weak current because of the disruption ofthe π-conjugation by the covalent bond between the benzene and the graphene. In all cases we findthat very strong or weak probe couplings suppress the current.
AU  - Horsfield,AP
AU  - Boleininger,M
AU  - D'Agosta,R
AU  - Iyer,V
AU  - Thong,A
AU  - Todorov,T
AU  - White,C
DO  - 10.1103/PhysRevB.94.075118
PY  - 2016///
SN  - 1550-235X
TI  - Efficient simulations with electronic open boundaries
T2  - Physical Review B
UR  - http://dx.doi.org/10.1103/PhysRevB.94.075118
UR  - http://hdl.handle.net/10044/1/38351
VL  - 94
ER  -
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