Multiscale simulation of thermal disruption in resistance switching process in amorphous carbon

26th IUPAP Conference on Computational Physics

物理学;计算机科学

Popov, A.M.^1 ; Shumkin, G.N.^2 ; Nikishin, N.G.^1

Moscow State University, Faculty of Computational Mathematics and Cybernetics, Moscow, Russia^1

IBM Systems and Technology Group, IBM Science and Technology Center, Moscow, Russia^2

关键词: Ab-initio quantum calculations;    Electronic subsystems;    Moscow State University;    Multi-scale simulation;    Quantum molecular dynamics;    Resistance switching;    Self consistent modeling;    Volt-ampere characteristics;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/640/1/012027/pdf
DOI  :  10.1088/1742-6596/640/1/012027

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

The switching of material atomic structure and electric conductivity is used in novel technologies of making memory on the base of phase change. The possibility of making memory on the base of amorphous carbon is shown in experiment [1]. Present work is directed to simulation of experimentally observed effects. Ab initio quantum calculations were used for simulation of atomic structure changes in amorphous carbon [2]. These simulations showed that the resistance change is connected with thermally induced effects. The temperature was supposed to be the function of time. In present paper we propose a new multiscale, self-consistent model which combines three levels of simulation scales and takes into account the space and time dependencies of the temperature. On the first level of quantum molecular dynamic we provide the calculations of phase change in atomic structure with space and time dependence of the temperature. Nose-Hover thermostats are used for MD simulations to reproduce space dependency of the temperature. It is shown that atomic structure is localized near graphitic layers in conducting dot. Structure parameter is used then on the next levels of the modeling. Modified Ehrenfest Molecular Dynamics is used on the second level. Switching evolution of electronic subsystem is obtained. In macroscopic scale level the heat conductivity equation for continuous media is used for calculation space-time dependence of the temperature. Joule heat source depends on structure parameter and electric conductivity profiles obtained on previous levels of modeling. Iterative procedure is self-consistently repeated combining three levels of simulation. Space localization of Joule heat source leads to the thermal disruption. Obtained results allow us to explain S-form of the Volt-Ampere characteristic observed in experiment. Simulations were performed on IBM Blue Gene/P supercomputer at Moscow State University.