02 Physical Sciences
http://hdl.handle.net/10453/15
Fri, 03 Jul 2015 12:08:43 GMT
20150703T12:08:43Z

SIESTA: Properties and Applications
http://hdl.handle.net/10453/30787
SIESTA: Properties and Applications
Ford, MJ
In this chapter a number of these properties are discussed through examples relevant to nanoscience and technology. The SIESTA methodology in detail in Chapter 2; the present chapter is intended as an accompaniment. The first three examples illustrate the general capabilities of the SIESTA code for problems containing relatively small numbers of atoms and that are amenable to standard diagonalization to solve the selfconsistent problem. The last example illustrates the divideandconquer linearscaling capabilities to tackle problems containing large numbers of atoms. © 2011 John Wiley & Sons, Inc.
Tue, 05 Jul 2011 00:00:00 GMT
http://hdl.handle.net/10453/30787
20110705T00:00:00Z

The apex of the family tree of protocols: Optimal rates and resource inequalities
http://hdl.handle.net/10453/29110
The apex of the family tree of protocols: Optimal rates and resource inequalities
Datta, Nilanjana; Hsieh, MinHsiu
We establish bounds on the maximum entanglement gain and minimum quantum communication cost of the fully quantum Slepian?Wolf (FQSW) protocol in the oneshot regime, which is considered to be at the apex of the existing family tree in quantum information theory. These quantities, which are expressed in terms of smooth min and maxentropies, reduce to the known rates of quantum communication cost and entanglement gain in the asymptotic independent and identically distributed scenario. We also provide an explicit proof of the optimality of these asymptotic rates. We introduce a resource inequality for the oneshot FQSW protocol, which in conjunction with our results yields achievable oneshot rates of its children protocols. In particular, it yields bounds on the oneshot quantum capacity of a noisy channel in terms of a single entropic quantity, unlike previous bounds. We also obtain an explicit expression for the achievable rate for oneshot state redistribution.
Sat, 01 Jan 2011 00:00:00 GMT
http://hdl.handle.net/10453/29110
20110101T00:00:00Z

A comparative density functional theory investigation of the mechanical and energetic properties of ZnS
http://hdl.handle.net/10453/29102
A comparative density functional theory investigation of the mechanical and energetic properties of ZnS
Feigl, CA; Russo, S; Barnard, A
Using density functional theory, the elastic and energetic properties of zinc sulphide (ZnS) in the zinc blende and wurtzite solid phases have been calculated with several energy functionals within local density and generalised gradient approximations. We report on the planewave energy cutoffs (which determine the size of the basis sets) and kpoint mesh density required to achieve energy convergence, and discuss the advantages of each functional with respect to computational expense and accuracy. This study provides a means of optimizing the tradeoff between accuracy and computational expense due to the choice of energy functional used in further ab initio studies of ZnS systems, and may serve as a guide as to how one may undertake such testing in the case of other materials.
Sat, 01 Jan 2011 00:00:00 GMT
http://hdl.handle.net/10453/29102
20110101T00:00:00Z

Size and ShapeDependent Phase Transformations in Wurtzite ZnS Nanostructures
http://hdl.handle.net/10453/29101
Size and ShapeDependent Phase Transformations in Wurtzite ZnS Nanostructures
Feigl, CA; Barnard, A; Russo, S
This paper describes the equilibrium morphologies of zinc sulfide nanoparticles in the wurtzite phase as a function of size, determined using ab initio Density Functional Theory (DFT) simulations and a shapedependent thermodynamic model predicting the Gibbs free energy of a nanoparticle. We investigate the relative stabilities of a variety of nanoparticle shapes based on the wurtzite structure and show how the aspect ratio of wurtzite nanorods moderates the sizedependent phase transformation to the zinc blende phase. We find that while wurtzite nanoparticles are thermodynamically unstable with respect to the low energy rhombic dodecahedron morphology in the zinc blende phase at all sizes, shape and sizedependent phase transformations occur when other zinc blende morphologies are present. Despite popular synthesis of zinc sulphide nanoparticles in the wurtzite phase, an indepth thermodynamic study relating to the relative stability of wurtzite shapes and comparison with the zinc blende phase does not exist. Therefore this is the first thermodynamic study describing how shape can determine the solid phase of zinc sulfide nanostructures, which will be of critical importance to experimental applications of nanostructured zinc sulfide, where phase and shape determines properties.
Sun, 01 Jan 2012 00:00:00 GMT
http://hdl.handle.net/10453/29101
20120101T00:00:00Z