Soumendu Datta

Communications: Elementary oxygen electrode reactions in the aprotic Li-air battery

We discuss the electrochemical reactions at the oxygen electrode of an aprotic Li-air battery. Using density functional theory to estimate the free energy of intermediates during the discharge and charge of the battery, we introduce a reaction free energy diagram and identify possible origins of the overpotential for both processes. We also address the question of electron conductivity through the Li(2)O(2) electrode and show that in the presence of Li vacancies Li(2)O(2) becomes a conductor.

Computational screening of perovskite metal oxides for optimal solar light capture

One of the possible solutions to the worlds rapidly increasing energy demand is the development of new photoelectrochemical cells with improved light absorption. This requires development of semiconductor materials which have appropriate bandgaps to absorb a large part of the solar spectrum at the same time as being stable in aqueous environments. Here we demonstrate an efficient, computational screening of relevant oxide and oxynitride materials based on electronic structure calculations resulting in the reduction of a vast space of 5400 different materials to only 15 promising candidates. The screening is based on an efficient and reliable way of calculating semiconductor band gaps. The outcome of the screening includes all already known successful materials of the types investigated plus some new ones which warrant further experimental investigation.

Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M(1)); and 1 alkali, alkaline earth or 3d/4d transition metal atom (M(2)) plus two to five (BH(4))(-) groups, i.e., M(1)M(2)(BH(4))(2-5), using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M(1)(Al/Mn/Fe)(BH(4))(4), (Li/Na)Zn(BH(4))(3), and (Na/K)(Ni/Co)(BH(4))(3) alloys are found to be the most promising, followed by selected M(1)(Nb/Rh)(BH(4))(4) alloys.

Magnetism in small bimetallic Mn-Co clusters

Effects of alloying on the electronic and magnetic properties of MnxCoy (x+y=n=2-5, x=0-n) and Mn2Co11 nanoalloy clusters are investigated using the density-functional theory. Unlike the bulk alloy ...

First-principles study of structural stability and electronic structure of CdS nanoclusters

Using first-principles density functional calculations, we have studied the structural stability of stoichiometric as well as nonstoichiometric CdS nanoclusters at ambient pressure with diameters ranging up to about 2.5 nm. Our study reveals that the relative stability of the two available structures for CdS, namely zincblende and wurtzite, depends sensitively on the details like surface geometry and/or surface chemistry. The associated band gap also exhibits nonmonotonic behavior as a function of cluster size. Our findings may shed light on reports of experimentally observed structures and associated electronic structures of CdS nanoclusters found in the literature.

Ab initio study of structural stability of small 3d late transition metal clusters: interplay of magnetization and hybridization

Using first-principles density functional theory based calculations, we analyze the structural stability of small clusters of 3

Engineering the magnetic properties of the Mn13 cluster by doping

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First principles study of bimetallic Ni13−nAgn nano-clusters (n = 0–13): Structural, mixing, electronic, and magnetic properties

late transition metals. We consider the relative stability of the two structures - layer-like structure with hexagonal closed packed stacking and more compact structure of icosahedral symmetry. We find that the Co clusters show an unusual stability in hexagonal symmetry compared to the small clusters of other members which are found to stabilize in icosahedral symmetry based structure. Our study reveals that this is driven by the interplay between the magnetic energy gain and the gain in covalency through

Vegard's law-like behavior for MnmTcn alloy clusters: a first-principles prediction

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First principles study of electronic structure for cubane-like and ring-shaped structures of M4O4, M4S4 clusters (M = Mn, Fe, Co, Ni, Cu)

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