Department of Physics
 
   
 
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Overview

Our research explores the interplay between structural, electronic, mechanical, optical, and thermoelectric properties of complex materials and related devices. We explain and predict effects which are of great importance in understanding the underlying fundamental science and in addition have the potential to inspire new technological developments. Our research attempts to reach across theoretical condensed matter physics, materials theory and real practical devices. Our work has been funded by the Department of Energy, the American Chemical Society, and the University of South Florida. 

 

First Principle Studies of Nanostructured Materials Properties

Research efforts are directed towards developing of fundamental relationship between the structural, electronic, mechanical, optical, and adsorption properties of complex materials. We use ab initio electronic structure methods such as density functional theory and tight binding models. Current projects are focused on applying first principles simulations investigating carbon nanotubes, graphene, graphene nanoribbons, and silicene nanoribbons. In particular, we are interested in how various factors such as mechanical defects, deformations, external fields, and the environment can be used to modulate graphitic and silicene nanostrucrure properties and aid the design of novel devices.

 

Long Ranged Interactions in Nanostructured Materials

The Casimir force was by predicted in 1948 by Henrik Casimir who showed that two perfectly conducting smooth plates in vacuum at zero K temperature should attract each other. This macroscopic effect is quantum mechanical in nature originating from the changes in the zero-point energy of the electromagnetic field. When the separation between the objects becomes less than the characteristic thermal wavelength, the electromagnetic excitations exchange is instanteneous, and the force is termed van der Waals force. The Casimir/van der Waals interactions are important in relation to the stability of a variety of nanostructured materials and the operation of nanostructure based devices. Currently, we are interested in the Casimir interaction of materials with quasi-one and two-dimensional structures. We develop various analytical and computational methods to investigate how the size, curvature, dimensionality and dielectric and magnetic properties influence the Casimir interaction between carbon nanotubes, graphenes, and graphene nanoribbons.  

 

Modeling of Devices

Our goal is to use the knowledge gained from the studies of fundamental properties of materials and explore the prediction of new device issues. We develop calculation methods and use commercially available computer codes to elucidate principles for new device operations. Currently we are interested in devices for profiling the roughness of surfaces, nanolithography tips, and devices for improved thermoelectric performances. 

 

 

Theory of Thermoelectric Materials and Their Applications

The main issue in thermoelectric research is to increase the materials figure of merit, a dimensionless quantitity which is closely related to the efficiency an actual device. Our research is directed towards exploring composites, polymer/nanostructured systems, and two-component materials for improved thermoelectric performance. In particular, we study the physical mechanisms influencing the thermal and charge transport in nanoscale formations and systems with interfaces and nanoscale inclusions. Ways to manipulate independently the thermopower, carrier conductivity, and thermal conductivity are also investigated.

 

 

Advanced Materials and Devices Theory Group of Prof. Lilia M. Woods
Funded by: