Galperin, Michael
Electron Transport in Condensed Phases. Dissipation and Relaxation Processes. Non-equilibrium Open Quantum Systems. Molecular Electronics.

Contact Information
Associate Professor of Chemistry and Biochemistry

Office: Urey Hall 3250
Phone: 858-246-0511
Group: View group members
2003 Ph.D., Chemical Physics, Tel Aviv University, Israel
1991 M.S., Theoretical Physics, Ural State University, Russia
Awards and Academic Honors
Hellman Faculty Fellow
DOE Early Career Award
LANL Director's Postdoctoral Fellowship
The Israel Chemical Society, J. Jortner prize
Research Interests
1. Nonequilibrium Atomic Limit. Theoretical tools employed in ab initio simulations in the field of molecular electronics combine methods of quantum chemistry and mesoscopic physics. Traditionally these methods are formulated in the language of effective single-particle orbitals. We argue that in many cases of practical importance a formulation in the language of many-body states, the nonequilibirum atomic limit, is preferable. We work with generalized quantum master equation (QME), Hubbard and pseudoparticle nonequilibrium Green functions (NEGF) formulations as many-body states based alternatives to the standard Redfield QME and NEGF methodologies.

2. Molecular Optoelectronics. The interaction of light with molecular conduction junctions is attracting growing interest as a challenging experimental and theoretical problem on one hand, and because of its potential application as a characterization and control tool on the other. In particular, Raman spectroscopy (following inelastic electron tunneling spectroscopy) has the potential to become an important diagnostic tool very much needed in the field of molecular electronics. Raman scattering was utilized to judge the presence and extent of the heating of molecular vibrations. These experiments are motivation for our theoretical formulation of transport and Raman scattering in molecular junctions. We develop both model and ab initio formulations accounting for both optical scattering and electron transport on the same footing.

3. Molecular Nanoplasmonics. Research in plasmonics is expanding its domains into several subfields. The unique optical properties of the surface plasmon-polariton (SPP) resonance, being the very foundation of plasmonics, find intriguing applications in optics of nanomaterials, materials with effective negative index of refraction, direct visualization, photovoltaics, single-molecule manipulation, and biotechnology. We work on modeling molecule-plasmon interactions, an essential ingredient in any realistic ab initio simulation for optical response of molecular junctions or optically driven open nanoscale devices.

4. Molecular Spintronics. The possibility of constructing spin devices utilizing organic molecules was demonstrated in a number of experiments, indicating the emergence of molecular spintronics as a new branch of molecular electronics. Magnetic field and electric potential were considered in the literature as controls for spin flux. We study theoretically molecular devices where spin rather than charge flux is the measured signal. Of particular interest are spin fluxes manipulated by an external electric field.

5. Quantum Thermodynamics and Full Counting Statistics. Thermodynamics of systems at nanoscale is at the heart of understanding and controlling the processes in the world of small systems from cells in biology to memory chips and optoelectric nano-devices in molecular electronics. Small size and open character of such devices implies importance of quantum and stochastic effects. Stochastic character of processes in open systems requires probabilistic description, which is intimately related to the full counting statistics (FCS). These issues have direct implications on defining meaningful notions of efficiency in thermoelectricity or photoelectricity.

6. Quantum Interference and Coherent Control in Junctions. The small size of molecules naturally poses questions on the role of coherences in the response properties of molecular devices. In molecular junctions experimental observations were attributed to interference effects in intramolecular electron transfer and elastic transport through single molecules, or to vibrationally induced decoherence. We model effects of quantum interference on charge and energy transport in molecular junctions, which either can be detected in the measurable transport characteristics or allow to control the molecular device.
Primary Research Area
Physical/Analytical Chemistry
Interdisciplinary interests
Computational and Theoretical

Outreach Activities
Promoting Diversity is an important part of the teaching process at the University. Facilitating professional advancement of students from all the groups is one of the core goals of my teaching activity. In particular, I promote equitable access to education for all the groups in my undergraduate classes. An example of promoting diversity is mentoring a female student of Asian origin within the framework of the research experience to undergraduates. In the past as a member of Admissions and Recruitment Committee, and currently as an external advisor to the committee I work to promote diversity of the department graduate program. My group is a mixture of scholars of different origins.
Image Gallery

Molecular many-body states formulation, the nonequilibrium atomic limit, for transport and optical response in molecular junctions.

Raman spectroscopy of an OPV3 junction.

Quantum dot in a Coulomb blockade regime by projection operator approach to non-equilibrium equation-of-motion (PO-NEGF EOM) method
Selected Publications