Structural, electronic and optical properties


Working Group: 
Prof. Alfonso BALDERESCHI
Prof. Alessandro MARVIN
Prof. Raffaele RESTA
Dr. Alessandro DE VITA
Dr. Maria PERESSI


Research activities:
Research activities concern the theoretical study of structural, electronic and optical properties of solids with a particular interest towards semiconductors and insulators.
The main research themes are:
1) Semiconductor interfaces
2) Dielectric polarization and other bulk properties of solids
3) Quasiparticle electronic properties
4) Numerical simulations on large systems
5) Surface optical properties


1) Semiconductor interfaces:
Theoretical studies of the structural and electronic properties of semiconductor - semiconductor and metal - semiconductor interfaces using Density Functional Theory in Local Density Approximation with pseudopotential method.
For semiconductor-semiconductor heterojunctions, the study is focused on interfaces containing wide gap semiconductors (II-VI) and interfaces between crystalline and amorphous semiconductors. We address the problem of band alignment and of the presence of interface states, and the effects of atomic interdiffusion.


2) Dielectric polarization and other bulk properties of solids:
Studies of the macroscopic and microscopic polarization of semiconductors and insulators (particularly oxides), in phenomena such as ferroelectricity, piezoelectricity, and lattice dynamics.

Investigations on the nature of the wavefunction of a nonconducting solid and on its Berry phase, which determines the macroscopic polarization. A related approach leads to studies of localization and to the calculation of localized orbitals. The latter have several promising applications.

Studies of the structural and electronic properties of amorphous semiconductors, with special interest to the relationship between topological and electronic properties.

Study of carbon nanostructures: simulation of single - layer nanotubes growth, non catalyzed and catalyzed with Co ions; effects of electronic "irradiation" on nano-onions.


3) Quasiparticle electronic properties:
Methods to calculate quasiparticle energies in solids within the GW scheme and applications to selected prototype systems (e.g. oxides).


4) Numerical simulation on large systems:
Development of semiempirical methods for accurate but efficient calculations in large systems.


5) Surface optical properties
Study of X-ray holography and optical aberration.


Publication List:
1998

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LAST UPDATE: APRIL 2000

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