The transition voltage of three different asymmetric Au/poly(phenylene) thiol/Au molecular junctions in which the central molecule is either benzene thiol, biphenyl thiol, or terphenyl thiol is investigated by first-principles quantum transport simulations. For all the junctions, the calculated transition voltage at positive polarity is in quantitative agreement with the experimental values and shows weak dependence on alterations of the Au-phenyl contact. When compared to the strong coupling at the Au-S contact, which dominates the alignment of various molecular orbitals with respect to the electrode Fermi level, the coupling at the Au-phenyl contact produces only a weak perturbation. Therefore, variations of the Au-phenyl contact can only have a minor influence on the transition voltage. These findings not only provide an explanation to the uniformity in the transition voltages found for π-conjugated molecules measured with different experimental methods, but also demonstrate the advantage of transition voltage spectroscopy as a tool for determining the positions of molecular levels in molecular devices.

1.
2.
H.
Song
,
M. A.
Reed
, and
T.
Lee
,
Adv. Mater.
23
,
1583
(
2011
).
3.
J. M.
Beebe
,
B.
Kim
,
J. W.
Gadzuk
,
C. D.
Frisbie
, and
J. G.
Kushmerick
,
Phys. Rev. Lett.
97
,
026801
(
2006
).
4.
J. M.
Beebe
,
B.
Kim
,
C. D.
Frisbie
, and
J. G.
Kushmerick
,
ACS Nano
2
,
827
(
2008
).
5.
K.
Liu
,
X.
Wang
, and
F.
Wang
,
ACS Nano
2
,
2315
(
2008
).
6.
AV.
Pakoulev
and
V.
Burtman
,
J. Phys. Chem. C
113
,
21413
(
2009
).
7.
G.
Wang
,
T.-W.
Kim
,
G.
Jo
, and
T.
Lee
,
J. Am. Chem. Soc.
131
,
5980
(
2009
).
8.
H.
Song
,
Y.
Kim
,
Y. H.
Jang
,
H.
Jeong
,
M. A.
Reed
, and
T.
Lee
,
Nature (London)
462
,
1039
(
2009
).
9.
A.
Tan
,
S.
Sadat
, and
P.
Reddy
,
Appl. Phys. Lett.
96
,
013110
(
2010
).
10.
G.
Noy
,
A.
Ophir
, and
Y.
Selzer
,
Angew. Chem., Int. Ed.
49
,
5734
(
2010
).
11.
N.
Bennett
,
G.
Xu
,
L. J.
Esdaile
,
H. L.
Anderson
,
J. E.
Macdonald
, and
M.
Elliott
,
Small
6
,
2604
(
2010
).
12.
S. H.
Choi
,
C.
Risko
,
M. C. R.
Delgado
,
B.
Kim
,
J.-L.
Brédas
, and
C. D.
Frisbie
,
J. Am. Chem. Soc.
132
,
4358
(
2010
).
13.
H.
Song
,
Y.
Kim
,
H.
Jeong
,
M. A.
Reed
, and
T.
Lee
,
J. Phys. Chem. C
114
,
20431
(
2010
).
14.
H.
Song
,
Y.
Kim
,
H.
Jeong
,
M. A.
Reed
, and
T.
Lee
,
J. Appl. Phys.
109
,
102419
(
2011
).
15.
G.
Wang
,
Y.
Kim
,
S.-I.
Na
,
Y. H.
Kahng
,
J.
Ku
,
S.
Park
,
Y. H.
Jang
,
D.-Y.
Kim
, and
T.
Lee
,
J. Phys. Chem. C
115
,
17979
(
2011
).
16.
D.
Xiang
,
Y.
Zhang
,
F.
Pyatkov
,
A.
Offenhäusser
, and
D.
Mayer
,
Chem. Commun.
47
,
4760
(
2011
).
17.
S.
Guo
,
J.
Hihath
,
I.
Díez-Pérez
, and
N.
Tao
,
J. Am. Chem. Soc.
133
,
19189
(
2011
).
18.
G.
Ricoeur
,
S.
Lenfant
,
D.
Guérin
, and
D.
Vuilaume
,
J. Phys. Chem. C
116
,
20722
(
2012
).
19.
M. L.
Trouwborst
,
C. A.
Martin
,
R. H. M.
Smit
,
C. M.
Guédon
,
T. A.
Baart
,
S. J.
van der Molen
, and
J. M.
van Ruitenbeek
,
Nano Lett.
11
,
614
(
2011
).
20.
E. H.
Huisman
,
C. M.
Guédon
,
B. J.
van Wees
, and
S. J.
van der Molen
,
Nano Lett.
9
,
3909
(
2009
).
21.
M.
Araidai
and
M.
Tsukada
,
Phys. Rev. B
81
,
235114
(
2010
).
23.
F.
Mirjani
,
J. M.
Thijssen
, and
S. J.
van der Molen
,
Phys. Rev. B
84
,
115402
(
2011
).
24.
I.
Bâldea
,
Phys. Rev. B
85
,
035442
(
2012
).
25.
I.
Bâldea
and
H.
Köppel
,
Phys. Lett. A
376
,
1472
(
2012
).
27.
I.
Bâldea
,
J. Am. Chem. Soc.
134
,
7958
(
2012
).
28.
A.
Vilan
,
D.
Cahen
, and
E.
Kraisler
,
ACS Nano
7
,
695
(
2013
).
29.
J.
Chen
,
T.
Markussen
, and
K. S.
Thygesen
,
Phys. Rev. B
82
,
121412
(R) (
2010
).
30.
T.
Markussen
,
J.
Chen
, and
K. S.
Thygesen
,
Phys. Rev. B
83
,
155407
(
2011
).
31.
Y.
Meir
and
N. S.
Wingreen
,
Phys. Rev. Lett.
68
,
2512
(
1992
).
32.
P.
Hohenberg
and
W.
Kohn
,
Phys. Rev.
136
,
B864
(
1964
).
33.
W.
Kohn
and
L. J.
Sham
,
Phys. Rev.
140
,
A1133
(
1965
).
34.
Y.
Xue
,
S.
Datta
, and
M. A.
Ratner
,
Chem. Phys.
281
,
151
(
2002
).
35.
M.
Brandbyge
,
J.-L.
Mozos
,
P.
Ordejón
,
J.
Taylor
, and
K.
Stokbro
,
Phys. Rev. B
65
,
165401
(
2002
).
36.
J.
Zhang
,
S.
Hou
,
R.
Li
,
Z.
Qian
,
R.
Han
,
Z.
Shen
,
X.
Zhao
, and
Z.
Xue
,
Nanotechnology
16
,
3057
(
2005
).
37.
R.
Li
,
J.
Zhang
,
S.
Hou
,
Z.
Qian
,
Z.
Shen
,
X.
Zhao
, and
Z.
Xue
,
Chem. Phys.
336
,
127
(
2007
).
38.
A. R.
Rocha
,
V. M.
Garcia-Suarez
,
S. W.
Bailey
,
C. J.
Lambert
,
J.
Ferrer
, and
S.
Sanvito
,
Nature Mater.
4
,
335
(
2005
).
39.
A. R.
Rocha
,
V. M.
García-Suárez
,
S.
Bailey
,
C.
Lambert
,
J.
Ferrer
, and
S.
Sanvito
,
Phys. Rev. B
73
,
085414
(
2006
).
40.
I.
Rungger
and
S.
Sanvito
,
Phys. Rev. B
78
,
035407
(
2008
).
41.
J. M.
Soler
,
E.
Artacho
,
J. D.
Gale
,
A.
García
,
J.
Junquera
,
P.
Ordejón
, and
D.
Sánchez-Portal
,
J. Phys.: Condens. Matter
14
,
2745
(
2002
).
42.
N.
Troullier
and
J.
Martins
,
Phys. Rev. B
43
,
1993
(
1991
).
43.
S.
García-Gil
,
A.
García
,
N.
Lorente
, and
P.
Ordejón
,
Phys. Rev. B
79
,
075441
(
2009
).
44.
K.
Wu
,
M.
Bai
,
S.
Sanvito
, and
S.
Hou
,
Nanotechnology
24
,
025203
(
2013
).
45.
J.
Perdew
,
K.
Burke
, and
M.
Ernzerhof
,
Phys. Rev. Lett.
77
,
3865
(
1996
).
46.
R.
Li
,
S.
Hou
,
J.
Zhang
,
Z.
Qian
,
Z.
Shen
, and
X.
Zhao
,
J. Chem. Phys.
125
,
194113
(
2006
).
47.
M.
Paulsson
and
M.
Brandbyge
,
Phys. Rev. B
76
,
115117
(
2007
).
48.
See supplementary material at http://dx.doi.org/10.1063/1.4830399 for the eigenchannel analysis and the transmission spectra at different gold-phenyl distances of the Au/biphenyl thiol/Au junction with the phenyl ring bonded to the Au(111) surface directly, the geometrical structure and the transport properties of the Au/biphenyl thiol/Au junctions with the phenyl ring bonded to the Au(111) surface through a four-atom gold cluster in a pyramid configuration and with the sulfur atom binding at the adatom site of the Au(111) surface, the geometrical structure and the transport properties of the Au/benzene thiol/Au and Au/terphenyl thiol/Au junctions with the phenyl ring bonded to the Au(111) surface through a gold adatom or a four-atom gold cluster, and the transport properties of the Au/benzene thiol/Au junction calculated using the LDA functional.
49.
A.
Tan
,
J.
Balachandran
,
B. D.
Dunietz
,
S. Y.
Jang
,
V.
Gavini
, and
P.
Reddy
,
Appl. Phys. Lett.
101
,
243107
(
2012
).
50.
J. P.
Perdew
and
Z.
Zunger
,
Phys. Rev. B
23
,
5048
(
1981
).
51.
J. B.
Neaton
,
M. S.
Hybertsen
, and
S. G.
Louie
,
Phys. Rev. Lett.
97
,
216405
(
2006
).
52.
K. S.
Thygesen
and
A.
Rubio
,
Phys. Rev. Lett.
102
,
046802
(
2009
).
53.
M.
Strange
,
C.
Rostgaard
,
H.
Häkkinene
, and
K. S.
Thygesen
,
Phys. Rev. B
83
,
115108
(
2011
).

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