Recent advances in theoretical methods and high performance computing allow for reliable first-principles predictions of complex nanostructured materials and devices. This talk will discuss four examples: (i) Nanotube-cluster systems, which behave as effective chemical sensors whose electrical response changes dramatically upon adsorption of small molecules onto the metal clusters. (ii) Non-equilibrium electron transport through molecules, as a stepping stone for the design of molecular-scale devices. (iii) Polarization and piezoelectric properties of PVDF and related polymers. In particular, we show that BN-based polymers offer 100% improvement in both ferro and piezoelectricity over PVDF-based polymers. (iv) Optical properties of semiconductor surfaces and water. We demonstrate that reflectance anisotropy of a semiconductor surface or interface provides a unique signature of its atomic structure, potentially enabling feedback-controlled growth with nearly monolayer resolution. Finally, our calculations explain the well-known redshift in the fundamental absorption of water as due to exciton delocalization upon aggregation.
In collaboration with W. Lu, S. Nakhmanson, M. Buongiorno Nardelli, V. Meunier, P. Hahn, W. G. Schmidt, S. Wang, and Q. Zhao
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