A microscopic approach to phononic energy transfer in nano structures
Author
Özpineci, Altuğ
Advisor
Çıracı, Salim
Date
1999Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Understanding of mechanisms for the energy transfer from and/or through
nano particles in contact with the large samples have become important in
various biological processes, molecular electronics and friction. In this thesis,
the phononic heat conductance of an atomic wire between two reservoirs, and
the vibrational relaxation of an atom adsorbed on a surface is studied. The
former problem is studied using the Keldysh formalism which yields the steady
state properties of the system. The dependence of the total conductance on
temperature, on the number of atoms in the wire and on the coefficient is
studied. It is found that the conductance shows quantal structure similar to
the electronic counterpart.
The reduced density matrix is used to study the latter problem. The time
evolution of the reduced density matrix has been evaluated for an arbitrary
system coupled to a heat bath. The formalism is then applied to study the
vibrational relaxation of an atom adsorbed on a surface. The frequency dependence
of the relaxation time is also determined.
Keywords
Heat ConductanceKeldysh Formalism
Phononic Heat Conductance Quantization
Reduced Density Matrix
Vibrational Relaxation