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Title: Many-body effects in transport and energy transfer

Abstract

Many-body effects is an important factor in predictions of properties of nano-materials and devices. Electron interactions with other electrons, electron-hole and plasmon excitations, and with nuclei give rise to a variety of measurable effects in transport and energy transfer on surfaces and interfaces. My research is focused on development of theoretical techniques to study open non-equilibrium molecular systems. Single molecules are used as building blocks of molecular devices for electronics, biosensors, nanoscale motors, controllable chemical reactivity and energy transfer. Sensitivity of molecules to reduction/oxidation/excitation makes tools of mesoscopic physics inconvenient, especially at resonance. Availability of developed methods of quantum chemistry and molecular spectroscopy for isolated molecular systems at equilibrium calls for development of techniques capable of utilizing these results to describe non-equilibrium molecular systems at surfaces and interfaces, thus taking into account all on-the-molecule correlations from the very start. Another important source of correlations is due to interactions between molecule and baths (e.g. for Kondo effect).Objectives of my research are: Development of theoretical techniques capable of describing non-equilibrium molecular systems in contact with baths in the language of many-body states of isolated molecule. Invention of approaches to describe electron-excitation interaction in realistic nonequilibrium molecular systems. This includes inelastic effects beyondmore » simple perturbation theory and for situations where Born-Oppenheimer approximation breaks down, optical response at non-equilibrium, and energy transport and transfer at surfaces and interfaces. Incorporation of non-adiabatic molecular dynamics (NAMD) into molecular device response to driving force in a form alternative to Ehrenfest dynamics and time-dependent scattering theory. NAMD plays important role in surface chemistry, radiationless transitions, and energy transfer at interfaces. It is the cause of phenomena ranging from current induced chemistry to switching and molecular motors. Development of practical approaches to simulation of strong molecule-contact correlation effects at non-equlibrium. Experiments are far beyond theoretical capabilities for realistic calculations. During the project I’m going to: Generalize two popular approaches to transport formulated in the language of many-body states: quantum master equation (QME) and non-equilibrium Hubbard Green function (NEHGF) technique. Study electron-excitations interactions: incorporate equilibrium molecular spectroscopy methods into non-equilibrium situation; reformulate previously derived expression for nonequilibrium Bose flux within the NEHGF approach; derive NEHGF equations for Bose-type Green functions; apply the technique to formulate calculational approach to optical and heat response in non-equilibrium molecular systems. develop NEHGF technique similar to Bloch-Maxwell formulation to predict molecular response in “hot spots”; consider possibility of employing exciton blocking effect as a control of molecular system response. Use many-body states formulation (step 1) to utilize fewest switches surface hopping method by Tully in situations of molecules near surfaces and at interfaces. Contrary to the usual formulation (including recent considerations of molecules near metallic surfaces) employing adiabatic states of the whole system (molecule plus contacts) I propose to describe hopping between diabatic states of the molecule. Develop scheme for description non-equilibrium Kondo effect (in particular, vibrationally assisted Kondo) for realistic molecular systems incorporating: a. combination of slave-boson technique (or its analog within Hubbard GF) used in NCA (or its generalization) with the self-consistent Born approximation; b. implementation of an extended version of equation-of-motion approach considered by the author previously, this time within NEHGF; c. the time-dependent density matrix renormalization group method; d. flow equation approach with NEHGF.« less

Authors:
ORCiD logo
Publication Date:
Research Org.:
Michael Galperin (UCSD)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
OSTI Identifier:
1485304
Report Number(s):
DE-SC0006422
DOE Contract Number:  
SC0006422
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; molecular junctions, quantum transport, optoelectronics, nonadiabatic molecular dynamics, Green functions

Citation Formats

Galperin, Michael. Many-body effects in transport and energy transfer. United States: N. p., 2015. Web. doi:10.2172/1485304.
Galperin, Michael. Many-body effects in transport and energy transfer. United States. https://doi.org/10.2172/1485304
Galperin, Michael. 2015. "Many-body effects in transport and energy transfer". United States. https://doi.org/10.2172/1485304. https://www.osti.gov/servlets/purl/1485304.
@article{osti_1485304,
title = {Many-body effects in transport and energy transfer},
author = {Galperin, Michael},
abstractNote = {Many-body effects is an important factor in predictions of properties of nano-materials and devices. Electron interactions with other electrons, electron-hole and plasmon excitations, and with nuclei give rise to a variety of measurable effects in transport and energy transfer on surfaces and interfaces. My research is focused on development of theoretical techniques to study open non-equilibrium molecular systems. Single molecules are used as building blocks of molecular devices for electronics, biosensors, nanoscale motors, controllable chemical reactivity and energy transfer. Sensitivity of molecules to reduction/oxidation/excitation makes tools of mesoscopic physics inconvenient, especially at resonance. Availability of developed methods of quantum chemistry and molecular spectroscopy for isolated molecular systems at equilibrium calls for development of techniques capable of utilizing these results to describe non-equilibrium molecular systems at surfaces and interfaces, thus taking into account all on-the-molecule correlations from the very start. Another important source of correlations is due to interactions between molecule and baths (e.g. for Kondo effect).Objectives of my research are: Development of theoretical techniques capable of describing non-equilibrium molecular systems in contact with baths in the language of many-body states of isolated molecule. Invention of approaches to describe electron-excitation interaction in realistic nonequilibrium molecular systems. This includes inelastic effects beyond simple perturbation theory and for situations where Born-Oppenheimer approximation breaks down, optical response at non-equilibrium, and energy transport and transfer at surfaces and interfaces. Incorporation of non-adiabatic molecular dynamics (NAMD) into molecular device response to driving force in a form alternative to Ehrenfest dynamics and time-dependent scattering theory. NAMD plays important role in surface chemistry, radiationless transitions, and energy transfer at interfaces. It is the cause of phenomena ranging from current induced chemistry to switching and molecular motors. Development of practical approaches to simulation of strong molecule-contact correlation effects at non-equlibrium. Experiments are far beyond theoretical capabilities for realistic calculations. During the project I’m going to: Generalize two popular approaches to transport formulated in the language of many-body states: quantum master equation (QME) and non-equilibrium Hubbard Green function (NEHGF) technique. Study electron-excitations interactions: incorporate equilibrium molecular spectroscopy methods into non-equilibrium situation; reformulate previously derived expression for nonequilibrium Bose flux within the NEHGF approach; derive NEHGF equations for Bose-type Green functions; apply the technique to formulate calculational approach to optical and heat response in non-equilibrium molecular systems. develop NEHGF technique similar to Bloch-Maxwell formulation to predict molecular response in “hot spots”; consider possibility of employing exciton blocking effect as a control of molecular system response. Use many-body states formulation (step 1) to utilize fewest switches surface hopping method by Tully in situations of molecules near surfaces and at interfaces. Contrary to the usual formulation (including recent considerations of molecules near metallic surfaces) employing adiabatic states of the whole system (molecule plus contacts) I propose to describe hopping between diabatic states of the molecule. Develop scheme for description non-equilibrium Kondo effect (in particular, vibrationally assisted Kondo) for realistic molecular systems incorporating: a. combination of slave-boson technique (or its analog within Hubbard GF) used in NCA (or its generalization) with the self-consistent Born approximation; b. implementation of an extended version of equation-of-motion approach considered by the author previously, this time within NEHGF; c. the time-dependent density matrix renormalization group method; d. flow equation approach with NEHGF.},
doi = {10.2172/1485304},
url = {https://www.osti.gov/biblio/1485304}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2015},
month = {6}
}