Dubi Group - Theoretical Nano-Science

Energy transport in nanoscale junctions

The thermo-electric (TE) effect is the conversion a temperature gradient into an electric potential, a property which may be beneficial for future energy technology. Theory indicates that molecular systems (i.e. Metal-molecule-metal junctions) can become superior thermoelectric converters and the thermoelectric response of a single-molecule junction have been measured in a set of impressive experiments. However, several of the experimental observations, including the value of the Seebeck coefficient and the observed large fluctuations, remain unexplained. My research is aimed at understanding the TE response of molecular junctions under various conditions, including the effects of junction geometry and contacts, presence of external fields (magnetic, microwave), optical excitations. The main goal is to understand how energy is transported in molecular junctions, and how it can be controlled and manipulated with external means.

Colloquium: Energy flow, Thermoelectricity and Fourier's law at the nanoscale

 Microwave-mediated thermoelectric effect in a quantum dot

Theory of thermoelectric effects in nanoscale junctions

Thermal transport in DNA nano-junctions

The DNA molecule is a key building-block of life. Thus, understanding the physical mechanisms which govern its behavior has become a great challenge. Specifically, understanding the denaturation transition of DNA (the seperation of the double-strand molecule into two single strands) is of great interest. My research is focused in understanding how energy flows through DNA nano-junctions as the DNA crosses the denaturation transition. The determination of the energy flow (via, e.g. the thermal conductance) has consequences to our understanding of DNA dynamics and the relaxation processes in DNA, to the way we model DNA in simulations, and for using DNA as a nano-technology template for future devices such as nano-scale thermal  switches.

Thermal transport as a probe for DNA denaturation

Tunable thermal switching of DNA-based nano-devices

Electronic properties of Heay-Fermion materials

Understanding how interactions between localized and conduction electrons affect (or indeed determine) the electronic properties of complex materials have been a top issue in material science. The topic has been revitalized in recent years, as new and ever-more sophisticated experimental tools have been introduced to strongly correlated materials on local scales, such as scanning tunneling spectroscopy. My research interest is in understanding the interplay between the global electronic structure and local nano-scale characteristics, i.e. how the electronic correlations affect the local STM images, and vice versa – how nano-scale features (such as disorder) are manifested in macro-scale measurements. Understanding these interrelations is a substantial step towards the interpertation of nano-scale measurements in this important class of materials. This is becoming an important tool in understanding and identifying their properties, bringin us closer to the goal of “materials by design” – the design of materials with specific electronic properties.

Local electronic structure and Fano interference in tunneling into a Kondo hole system

Hidden-order pseudogap in URu2Si2

How Kondo-holes create intense nano-scale heavy-Fermion hybridization disorder

Hybridization wave as the 'Hidden Order' in URu2Si2

Collaborators: Past and Present

Yigal Meir (BGU)

M. Di Ventra (UCSD)

A. Sharoni (BIU)

M. Zwolak (OSU)