Theory of oxide surfaces, interfaces, supported clusters

Pacchioni research group

The understanding of the structure-properties relationship is of fundamental importance for the design  of  new  materials.  In  our  group various  models  are  employed  to  study  the  electronic structure  of  inorganic  and  ceramic  materials  in  combination  with  highly accurate  quantum-mechanical techniques. Particularly important is the role of theory in the study of point defects, impurities in solids, active sites or functional groups on surfaces, phenomena like atomic and molecular chemisorption, ultrathin films, supported clusters, light-matter interactions, and for the interpretation of various spectroscopies, IR and Raman, X-ray absorption and photoemission, EPR and NMR, optical transitions, STM etc.

Oxide surfaces and thin oxide films

Ultrathin oxide films grown on metal supports represent a new class of materials with unprecedented properties. Our activity is directed towards the determination of their electronic and structural properties: work function changes, presence of nanoholes or regular arrays of adsorption and reactive sites, etc.

Supported clusters

Metal nanoclusters are of great interest as models of supported catalysts. We study the interaction and stabilization of the metal clusters at specific sites of the support like oxygen vacancies and other defects. We investigate the possible electronic modification of metal clusters on ultrathin insulating films due to electron tunneling phenomena from the metal support (charging, change in shape and reactivity, etc.). We also study the reactivity of supported clusters in elementary steps of catalytic reactions.

Defects and dopants in oxides

We investigate on the nature of point defects in oxide materials for photocatalysis, photoelectrochemistry, microelectronics, fiber optics etc., in particular amorphous and crystalline TiO2, ZnO, WO3, SiO2, alkaline earth oxides. The activity is directed toward the determination of stability, structure, and spectral properties of intrinsic and extrinsic point defects (vacancies, metal and non-metal dopants, codopants, hydroxyl groups, trapped electrons, etc.) and their interplay through charge transfer processes. Particular attention is devoted to the study of optical absorption for activation in the visible region and of electron spin resonance spectra for identification of paramagnetic centres.

Oxide semiconductors and heterojunctions

Heterojunctions between semiconductors (notably oxides) are a class of materials attracting growing attention in the field of photocatalysis. This research line aims at the accurate description of the band alignment, charge transfer phenomena, and charge carrier separation at the junction by means of state-of-the-art DFT calculations.

Research Team

Facilities

Main facilities

  • Total computing power of 960 AMD Opteron cores in local facilities.
  • Access to CINECA supercomputing centre facilities via an institutional account financed by the University as well as via peer-reviewed scientific proposals.
superfici di ossidi, interfacce, e cluster supportati