Abstract

We study the Hamiltonian dynamics of a free particle injected onto a chain containing a periodic array of harmonic oscillators in thermal equilibrium. The particle interacts locally with each oscillator, with an interaction that is linear in the oscillator coordinate and independent of the particle's position when it is within a finite interaction range. At long times the particle exhibits diffusive motion, with an ensemble averaged mean-squared displacement that is linear in time. The diffusion constant at high temperatures follows a power law D~T 5/2 for all parameter values studied. At low temperatures particle transport changes to a hopping process in which the particle is bound for considerable periods of time to a single oscillator before it is able to escape and explore the rest of the chain. A different power law, D~T 3/4, emerges in this limit. A thermal distribution of particles exhibits thermally activated diffusion at low temperatures as a result of classically self-trapped polaronic states.

Department(s)

Physics

Sponsor(s)

National Science Foundation (U.S.)

Keywords and Phrases

Diffusion; Harmonic oscillators; Hopping conduction; Polarons

International Standard Serial Number (ISSN)

2469-9950

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2006 American Physical Society (APS), All rights reserved.

Publication Date

01 Jan 2006

Download

Full Text Link

Included in

Physics Commons

Share

 
COinS