Ab initio studies of polyanionic clustering in liquid alloys

“…The effects of the addition of alkali metals on the electronic and structural properties of liquid Te have been extensively studied by both experimental [10][11][12][13][14][15] and theoretical [16][17][18] methods so far. With increasing alkali-metal concentration, the electrical conductivity decreases monotonically, [10][11][12] i.e., the electrical conductivity of pure liquid Te is about 2000 ⍀ −1 cm −1 , and it is only about 1 ⍀ −1 cm −1 at an alkalimetal concentration of 50%.…”

Section: Introductionmentioning

confidence: 99%

Chain structure and electronic states of liquid Rb-Se mixtures byab initiomolecular-dynamics simulations

Shimojo

Hoshino

2006

Phys. Rev. B

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The effects of excess electronic charges transferred from alkali metals to Se atoms on the chain structure in liquid Rb x Se 1−x for x ഛ 0.5 are investigated by means of ab initio molecular-dynamics simulations. It is found that the interaction between Se chains is enhanced by the transferred electrons, and that the average length of Se chains becomes shorter with increasing alkali-metal concentration. The shortening of Se chains is responsible for an increase of electronic states at the Fermi level, which explains the observed increase of the electrical conductivity on the addition of alkali metals. At the equiatomic concentration, there are almost no electronic states at the Fermi level due to the formation of Se 2 2− dimers. The alkali-metal-concentration dependence of the bonding properties between Se atoms is discussed in comparison with liquid alkali-metal tellurides based on a population analysis.

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“…It is well established now [2] that the properties of the liquid alkali-group IV alloys also show particular properties, as a large peak in the resistivity and other thermodynamic properties, at the equiatomic composition, and a prepeak in the total structure factor at rather small wavevectors, around 1 Å À1 , which somehow suggest the survival of clusters in the liquid alloy. The presence of these clusters in the liquid, although deformed, and dynamically breaking and forming, has been in fact observed in ab initio simulations [3,4], which permit a detailed study of the structure of a system providing the coordinates of the atoms at any time. Alkali-group III alloys on the other hand are in general more complex, their properties being dictated more by the so called Wade rules, which are related to boron chemistry [5].…”

Section: Introductionmentioning

confidence: 94%