Berkeley Lab Scientific Computing Seminar

Date:

Friday, August 17, 2007

Time:

1:00pm-2:00pm

Location:

Building 50A-5132

Seminar Speaker:

Denis O. Demchenko
Scientific Computing Group
CRD, LBNL

Title:

Theory of Semiconductor Nanostructures: computation and experiment

Abstract:

Progress in fabricating a variety of types of nanocrystals e.g., dots, wires, nanorod superlattices, tetrapods, etc., creates a need for methods to calculate the properties of these nanostructures. However, the direct ab initio density functional theory (DFT) methods are not readily applicable to the nanostructures, due to the large number of atoms in most experimental nanostructures. Additional problem arises in interpreting nanostructure transport experiments, which often involve metallic electrode/nanostructure contact. The popular local density approximation (LDA) fails to describe such a nanocontact due to the presence of electrode induced polarization potential, absent from LDA. Driven by experiment, new theoretical methods were developed, such as charge patching, folded spectrum, surface polarization potential, etc. Here we will apply them to CdS quantum dots, CdSe/metal nanocontacts, and recently synthesized A_2 S/CdS nanorod superlattices. The latter is an example of research done by theory and experiment as an integral process, rather than explanation of experimental data by theory post factum.

Sponsor of Seminar:

Lin-Wang Wang

Scientific Computing

Contact Esmond G. Ng EGNg@lbl.gov