40th National Conference on Theoretical Physics (NCTP-40)
Hội nghị Vật lý lý thuyết toàn quốc lần thứ 40
Đà Lạt, 27-29 July 2015
in association with: 3rd International Workshop on Theoretical and
Computational Physics: Complex Systems and Interdisciplinary Physics

Program

P.33 -- Poster, NCTP-40

Date: Tuesday, 28 July 2015

Time: 08h30 - 10h00

Dynamics Simulation of Backward Diffusion Based on Random Walk Theory

Vu Ba Dung and Bui Huu Nguyen

Ha Noi University of Mining and Geology - Duc Thang ward, Bac Tu Liem district, Hanoi, Vietnam

Some results of diffusion study in silicon showed that diffusion of the self-interstitial and vacancy could be backward diffusion and their diffusivity could be negative [1]. The backward diffusion process and negative diffusivity is contrary to the fundamental laws of diffusion such as Fick’s law and Onsager’s law, namely the diffusive flux of backward diffusion goes from regions of low concentration to regions of high concentration. Backward diffusion could be explained that the thermal velocity of molecules in low concentration is greater than two times. Moreover, based on the thermodynamics and random walk theory the backward diffusion process are be simulated. Results of simulation is corresponding to theory. They also showed that when thermal velocity of molecules in low concentration area is greater than two times in high concentration area, the backward diffusion is occurred.

Presenter: Bui Huu Nguyen


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