02 Physical Sciences
http://hdl.handle.net/10453/15
2015-07-31T09:53:46Z
2015-07-31T09:53:46Z
SIESTA: Properties and Applications
Ford, MJ
http://hdl.handle.net/10453/30787
2015-03-13T03:42:51Z
2011-07-05T00:00:00Z
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 self-consistent problem. The last example illustrates the divide-and-conquer linear-scaling capabilities to tackle problems containing large numbers of atoms. © 2011 John Wiley & Sons, Inc.
2011-07-05T00:00:00Z
The apex of the family tree of protocols: Optimal rates and resource inequalities
Datta, Nilanjana
Hsieh, Min-Hsiu
http://hdl.handle.net/10453/29110
2014-10-10T15:27:22Z
2011-01-01T00:00:00Z
The apex of the family tree of protocols: Optimal rates and resource inequalities
Datta, Nilanjana; Hsieh, Min-Hsiu
We establish bounds on the maximum entanglement gain and minimum quantum communication cost of the fully quantum Slepian?Wolf (FQSW) protocol in the one-shot 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 max-entropies, 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 one-shot FQSW protocol, which in conjunction with our results yields achievable one-shot rates of its children protocols. In particular, it yields bounds on the one-shot 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 one-shot state redistribution.
2011-01-01T00:00:00Z
A comparative density functional theory investigation of the mechanical and energetic properties of ZnS
Feigl, CA
Russo, S
Barnard, A
http://hdl.handle.net/10453/29102
2015-03-13T02:59:39Z
2011-01-01T00:00:00Z
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 plane-wave energy cut-offs (which determine the size of the basis sets) and k-point 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 trade-off 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.
2011-01-01T00:00:00Z
Size- and Shape-Dependent Phase Transformations in Wurtzite ZnS Nanostructures
Feigl, CA
Barnard, A
Russo, S
http://hdl.handle.net/10453/29101
2015-03-13T02:59:37Z
2012-01-01T00:00:00Z
Size- and Shape-Dependent 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 shape-dependent 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 size-dependent 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 size-dependent phase transformations occur when other zinc blende morphologies are present. Despite popular synthesis of zinc sulphide nanoparticles in the wurtzite phase, an in-depth 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.
2012-01-01T00:00:00Z