title: Conductance saturation in a series of highly transmitting molecular junctions.
abstract: Revealing the mechanisms of electronic transport through metal-molecule interfaces is of central importance for a variety of molecule-based devices. A key method for understanding these mechanisms is based on the study of conductance versus molecule length in molecular junctions. However, previous works focused on transport governed either by coherent tunnelling or hopping, both at low conductance. Here, we study the upper limit of conductance across metal-molecule-metal interfaces. Using highly conducting single-molecule junctions based on oligoacenes with increasing length, we find that the conductance saturates at an upper limit where it is independent of molecule length. With the aid of two prototype systems, in which the molecules are contacted by either Ag or Pt electrodes, we find two different possible origins for conductance saturation. The results are explained by an intuitive model, backed by ab initio calculations. Our findings shed light on the mechanisms that constrain the conductance of metal-molecule interfaces at the high-transmission limit.
authors.affiliation: Chemical Physics, Weizmann Institute of Science, 7610001 Rehovot, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Yelin
authors.affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93053 Regensburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Korytár
authors.affiliation: Chemical Physics, Weizmann Institute of Science, 7610001 Rehovot, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Sukenik
authors.affiliation: Chemical Physics, Weizmann Institute of Science, 7610001 Rehovot, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Vardimon
authors.affiliation: Department of Chemistry, Columbia University, New York 10027, USA.
authors.forename: B
authors.initials: B
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Columbia University, New York 10027, USA.
authors.forename: C
authors.initials: C
authors.lastname: Nuckolls
authors.affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93053 Regensburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Evers
authors.affiliation: Chemical Physics, Weizmann Institute of Science, 7610001 Rehovot, Israel.
authors.forename: O
authors.initials: O
authors.lastname: Tal
references.citation: Phys Rev Lett. 2005 Apr 1;94(12):126102
references.pmid: 15903941
references.citation: Phys Rev Lett. 1996 Oct 28;77(18):3865-3868
references.pmid: 10062328
references.citation: Nat Nanotechnol. 2013 Apr;8(4):282-7
references.pmid: 23503093
references.citation: J Phys Condens Matter. 2010 Apr 7;22(13):133001
references.pmid: 21389503
references.citation: Nat Nanotechnol. 2011 Apr;6(4):226-31
references.pmid: 21336268
references.citation: Nat Mater. 2015 May;14(5):517-22
references.pmid: 25686263
references.citation: J Am Chem Soc. 2012 Mar 21;134(11):5262-75
references.pmid: 22352944
references.citation: Phys Rev Lett. 2007 May 18;98(20):206801
references.pmid: 17677725
references.citation: J Am Chem Soc. 2007 May 30;129(21):6714-5
references.pmid: 17488083
references.citation: Nano Lett. 2006 Jun;6(6):1240-4
references.pmid: 16771587
references.citation: J Chem Theory Comput. 2013 Jun 11;9(6):2801-15
references.pmid: 26583870
references.citation: Phys Rev Lett. 2008 Jul 25;101(4):046801
references.pmid: 18764352
references.citation: Small. 2010 Jul 19;6(14):1529-35
references.pmid: 20578111
references.citation: Nanotechnology. 2010 Dec 10;21(49):495202
references.pmid: 21079288
references.citation: Nano Lett. 2013 Jul 10;13(7):3358-64
references.pmid: 23731268
references.citation: Nat Commun. 2014 Sep 23;5:5000
references.pmid: 25247247
references.citation: J Am Chem Soc. 2011 Dec 14;133(49):19864-77
references.pmid: 22017173
references.citation: Nature. 2006 Aug 24;442(7105):904-7
references.pmid: 16929295
references.citation: Nat Nanotechnol. 2009 Sep;4(9):551-6
references.pmid: 19734925
references.citation: Nano Lett. 2013 May 8;13(5):1956-61
references.pmid: 23517527
references.citation: Nat Nanotechnol. 2011 May 08;6(6):353-7
references.pmid: 21552252
references.citation: Phys Rev B Condens Matter. 1993 Nov 15;48(19):14721-14724
references.pmid: 10007910
references.citation: Nat Nanotechnol. 2014 Dec;9(12):1040-6
references.pmid: 25344689
references.citation: Nano Lett. 2015 Jun 10;15(6):3716-22
references.pmid: 26020454
references.citation: Nano Lett. 2011 Sep 14;11(9):3734-8
references.pmid: 21805977
references.citation: J Am Chem Soc. 2005 Feb 9;127(5):1384-5
references.pmid: 15686365
references.citation: J Chem Phys. 2007 May 7;126(17):174101
references.pmid: 17492851
references.citation: Nat Mater. 2005 Apr;4(4):335-9
references.pmid: 15750597
references.citation: Nano Lett. 2009 Nov;9(11):3949-53
references.pmid: 19751067
references.citation: Nat Chem. 2012 Jun 10;4(7):574-8
references.pmid: 22717444
references.citation: Phys Rev Lett. 2009 Mar 27;102(12):126803
references.pmid: 19392306