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Title: Theory and computational modelling of ultra-thin film capacitors
Author: Selenu, S.
ISNI:       0000 0001 3393 3526
Awarding Body: Queens -Belfast
Current Institution: Queen's University Belfast
Date of Award: 2008
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The topic of this thesis is the study of dielectric response of ultra-thin STO films in nano capacitors in external applied electric fields present in the simulation cell. Our model refers to a common ab initio model scheme, and several aspects of the dielectric response of STO films interfaced with a metal electrode where faced. The principal aspect was the modelling of such films in an applied electric field, and the task has been successfully implemented in the context of first principles calculation scheme. In fact, it is possible to interface a layer of metal with a layer of such dielectric material and apply an external field so that the task has been achieved even using , periodic boundary conditions in a DFT context. We prove that it is possible to define and calculate the high frequency dielectric constant foe. The former is given by the ratio.. I present, in the second part, a general formula with the aim to calculate the 'group velocity', of a quantal system, where I firstly developed my derivation oa a real vector field in an abstract geometrical way. I have discussed a particular application aimed to condesed matter where I have shown that at order of expansion of the Hamiltonian of power of lie it is possible to obtain the qunatum Lorentz force the expression of the power delivered by an external electromagnetic field to the electronic sub-system. I also wrote the Berry phase in a mechanical way and introduce a new quantum phase. I have shown that those phases can be derived by two 'new' vector fields corresponding to: 'angular-momentum' field and a vector field that does not have any classical analogue.
Supervisor: Not available Sponsor: Not available
Qualification Name: Queens -Belfast, 2008 Qualification Level: Doctoral
EThOS ID:  DOI: Not available