Colin Lambert - Selected Publications#

[1] Precision control of single-molecule electrical junctions, W. Haiss, C. Wang, I. Grace, A.S. Batsanov, D.J. Schiffrin, S.J. Higgins, M.R. Bryce, C.J. Lambert and R.J. Nichols, Nature Materials, 5 995 (2006). This joint theory/experimental paper exemplifies how the predictive capabilities of SMEAGOL can guide, interpret and stimulate new experiments. It shows how the angle of contact between a molecule and an electrode can be used to control electrical properties. The figure opposite shows how the electronic density of states varies with tilt angle. From a theoretical viewpoint, such experiments are a novel form of spectroscopy, which probes electronic properties in the vicinity of the HOMO-LUMO gap.

[2] Long-range electron tunnelling in oligo-porphyrin molecular wires, G. Sedghi, L. J. Esdaile, H. L. Anderson, V. M. García-Suárez, C.J. Lambert, S. Martin, D.Bethell, S. J. Higgins and R. J. Nichols, Nature Nano., 6 517 (2011). This joint theory/experimental paper analyses the electrical properties of a series of porphyrin chains. Calculations based on SMEAGOL and an accompanying analytical model confirm that the observed temperature and length dependence is consistent with phase-coherent tunnelling through the whole molecular junction. This means that porphyrin-based molecular wires could sustain quantum effects in nanoelectronic and thermoelectric devices.

[3] Single Molecular Conductance of Tolanes: Experimental and Theoretical Study on the Junction Evolution Dependent on the Anchoring Group, W. Hong, D. Z. Manrique, P. Moreno-Garcia, M. Gulcur, A. Mishchenko, C.J. Lambert, M.R. Bryce and T. Wandlowski, JACS 134 2292-2304 (2012). This paper demonstrates that the slow decay of electrical conductance with length of atomic chains of oligoynes depends on the type of terminal group used to anchor the chain to electrodes. The paper also illustrates state of the art theory and modelling capabilities, which allowed the prediction of whole break-junction ‘pulling curves’ of conductance versus electrode separation. This capability is now incorporated into GOLLUM.

[4] Correlations between Molecular Structure and Single-Junction Conductance: A Case Study with Oligo(phenylene-ethynylene)-Type Wires, V. Kaliginedi, P. Moreno-Garcia, H. Valkenier, WJ Hong, V.M. Garcia-Suarez, P. Buiter, J.L.H. Otten, J.C. Hummelen, C.J. Lambert and T. Wandlowski, JACS 134 5262 (2012) Building upon Lambert’s ideas regarding the role of Fano resonances in single-molecule electron transport, a family of molecules was selected for screening by break-junction measurements and ab initio modelling. This confirmed experimentally that quantum interference controls room-temperature electrical conductance through single molecules and has the potential to produce enhanced thermoelectrical performance.

[5] Towards molecular spintronics, A. Reily Rocha#, V.M. García-Suárez, S.W. Bailey, C.J. Lambert, J. Ferrer and S. Sanvito, Nature Materials 4, 335 (2005). This paper presents the first ab initio predictions for the magnetoresistance of spin valves formed from single molecules. It analyses single-molecule analogues of metallic spin valves and tunnelling magnetoresistance. In both cases, a large magnetoresistance is predicted, which was confirmed by later experiments. It also reports a breakthrough in the first principles simulation of non-equilibrium transport through nanostructures, encapsulated in the transport code SMEAGOL.

[6] Spin and molecular electronics in atomically-generated orbital landscapes, A.R. Rocha, V.M. Garcia-Suarez, S. Bailey, C. Lambert, S. Sanvito and J. Ferrer, Phys. Rev. B73 085414 (2006) This paper presents the non-equilibrium Green’s function formalism underpinning the approach to ab initio electron transport reported above. The associated code ‘SMEAGOL’ has since been adopted by over 150 groups worldwide.

[7] Molecular design and control of fullerene-based bi-thermoelectric materials, Laura Rincón-García, Ali K. Ismael, Charalambos Evangeli, Iain Grace, Gabino Rubio-Bollinger, Kyriakos Porfyrakis, Nicolás Agraït, and Colin J. Lambert, Nature Materials, 15, 289–293 (2016). Calculations presented in this paper show that Sc3N inside the fullerene cage creates a sharp resonance near the Fermi level, whose energetic location, and associated thermopower, can be tuned by applying pressure. These results reveal that Sc3N@C80 is a bi-thermoelectric material, exhibiting both positive and negative thermopower, and provide an unambiguous demonstration of the importance of transport resonances in molecular junctions.

[7] Conductance Enlargement in Pico-scale Electro-burnt Graphene Nanojunctions, Sadeghi, H.; Mol, J.; Lau, C.; Briggs, G. A. D.; Warner, J.; Lambert, C. J., Proceedings of the National Academy of Sciences 9, 2658-2663 (2015) Lambert’s theory predicts and experiment confirms that picoscale graphene junctions, currently being developed for single-molecule electronics, themselves exhibit quantum interference effects just before they break. Consequently both molecules and electrodes must be treated holistically when predicting transport through such structures.

[9] (219 citations) Generalised Landauer formulae for quasi-particle transport in inhomogeneous superconductors, Lambert C.J., J. Phys.: Condens. Matter, 36579 (1991)
This seminal paper contains the first derivation of fundamental current-voltage relations for inhomogeneous superconducting nanostructures with normal contacts. These formulae represent a new multiple-scattering approach to transport which is distinct from more established quasi-classical and semi-classical theories and underpin many calculations of mesoscopic phenomena in hybrid normal-superconducting structures.

[10] (304 citations) Phase-coherent transport in superconducting nanostructures, C.J. Lambert and R. Raimondi, J. Phys.: Condens. Matter 10 901 (1998) This article surveys the field of electron transport in hybrid normal-superconducting nanostructures. Whereas the community using multiple-scattering techniques tends to use the language of Andreev scattering, the quasi-classical community uses the language of long-range proximity effects. For the first time, by presenting both theories on an equal footing, this article clarifies their intimate relationship.