Date: Thursday, Feb 18th
Presenter: Dr. David Evans, Sharp Laboratories of America
Nanostructures are becoming increasingly important as technological components for applications ranging widely from sensors and photonics to energy harvesting, and even conventional electronic devices. Even so, much of the science of the nanoscale still remains observationally based and generally empirical. Nevertheless, there are a number of research efforts directed toward modeling at the atomic scale and consequent understanding of nanoscale physics. However, classical thermodynamic concepts have not been widely applied to nanostructures. The reason for this is quite simple: conventional thermodynamics is conceptually limited to macroscopic systems. This is both a strength and weakness. Indeed, because the underlying microscopic physics is generally treated in an grossly averaged sense, thermodynamics can be widely applied to any type of material or process for which temperature is well-defined. However, this also generally precludes consideration of very small systems. To remedy this, more than forty years ago Terrell L. Hill, then at the University of Oregon, developed an approach extending thermodynamics to ?small scales? such as characterized by colloid particles, surfactant micelles, protein molecules and similar structures. This field languished in the intervening decades, but now such structures are recognized as falling under the general rubric of ?nanotechnology?. In this talk, Hill?s methods will be discussed and applied to small silicon structures. These concepts will be further illustrated with specific results derived from density functional theory.