Modeling contact formation between atomic-sized gold tips via molecular dynamics

3rd International Conference on Mathematical Modeling in Physical Sciences

物理学;数学

Dednam, W.^1,2 ; Sabater, C.^1,4 ; Fernandez, M.A.^1 ; Untiedt, C.^1 ; Palacios, J.J.^3 ; Caturla, M.J.^1

Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig, Alicante

E-03690, Spain^1

Department of Physics, Science Campus, University of South Africa, Private Bag X6, Florida Park

1710, South Africa^2

Departamento de Física de la Materia Condensada, Universidad Autonoma de Madrid, Cantoblanco, Madrid

28049, Spain^3

Huygens-Kamerlingh Onnes Laboratorium, Leiden University, Niels Bohrweg 2, CA Leiden

2333, Netherlands^4

关键词: Atomic configuration;    Conductance values;    Crystallographic orientations;    Electronic transport;    Face-centred cubic;    Geometric configurations;    Molecular dynamics simulations;    Nano-sized electrodes;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/574/1/012045/pdf
DOI  :  10.1088/1742-6596/574/1/012045

来源: IOP

【 摘 要 】

The formation and rupture of atomic-sized contacts is modelled by means of molecular dynamics simulations. Such nano-contacts are realized in scanning tunnelling microscope and mechanically controlled break junction experiments. These instruments routinely measure the conductance across the nano-sized electrodes as they are brought into contact and separated, permitting conductance traces to be recorded that are plots of conductance versus the distance between the electrodes. One interesting feature of the conductance traces is that for some metals and geometric configurations a jump in the value of the conductance is observed right before contact between the electrodes, a phenomenon known as jump-to-contact. This paper considers, from a computational point of view, the dynamics of contact between two gold nano-electrodes. Repeated indentation of the two surfaces on each other is performed in two crystallographic orientations of face-centred cubic gold, namely (001) and (111). Ultimately, the intention is to identify the structures at the atomic level at the moment of first contact between the surfaces, since the value of the conductance is related to the minimum cross-section in the contact region. Conductance values obtained in this way are determined using first principles electronic transport calculations, with atomic configurations taken from the molecular dynamics simulations serving as input structures.