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Lu, Zhong-Yi; Wang, Cai‐Zhuang; Ho, Kai‐Ming

doi:10.1103/physrevb.61.2329

Cited by 188 publications

(161 citation statements)

References 35 publications

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“…In most cases, the five runs yielded the same global minimum. For the MSW cluster Si 28 and Si 29 , however, two runs resulted in an oblate local-minimum structure. When we set the temperature T*ϭ0.25, all five runs led to the same prolate global-minimum structure.…”

Section: Basin-hopping Global Optimization Methodsmentioning

confidence: 99%

“…A central issue concerning the small clusters Si n is their lowest-energy geometric structures, namely, their global minima as a function of the cluster size n. For nр7, the global minima are firmly established by both ab initio calculations and Raman or infrared spectroscopy measurements, whereas for nр13 the global minima are also well established by ab initio calculations. 10,28,29 For 14рnр20, the global minima have been predicted based on semiempirical tight-binding ͑TB͒ and density functional theory ͑DFT͒ calculations 23,24 coupled with the genetic algorithm ͑GA͒ global optimization technique. 30 For Si 20 , in particular, the global minimum has been confirmed by the quantum Monte Carlo calculation.…”

Section: Introductionmentioning

confidence: 99%

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Global geometry optimization of silicon clusters described by three empirical potentials

Yoo

Zeng

2003

The Journal of Chemical Physics

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The ''basic-hopping'' global optimization technique developed by Wales and Doye is employed to study the global minima of silicon clusters Si n (3рnр30) with three empirical potentials: the Stillinger-Weber ͑SW͒, the modified Stillinger-Weber ͑MSW͒, and the Gong potentials. For the small-sized SW and Gong clusters (3рnр15), it is found that the global minima obtained based on the basin-hopping method are identical to those reported by using the genetic algorithm ͓Iwamatsu, J. Chem. Phys. 112, 10976 ͑2000͔͒, as well as with those by using molecular dynamics and the steepest-descent quench ͑SDQ͒ method ͓Feuston, Kalia, and Vashishta, Phys. Rev. B 37, 6297 ͑1988͔͒. However, for the mid-sized SW clusters (16рnр20), the global minima obtained differ from those based on the SDQ method, e.g., the appearance of the endohedral atom with fivefold coordination starting at nϭ17, as opposed to nϭ19. For larger SW clusters (20рn р30), it is found that the ''bulklike'' endohedral atom with tetrahedral coordination starts at n ϭ20. In particular, the overall structural features of SW Si 21 , Si 23 , Si 25 , and Si 28 are nearly identical to the MSW counterparts. With the SW Si 21 as the starting structure, a geometric optimization at the B3LYP/6-31G͑d͒ level of density-functional theory yields an isomer similar to the ground-stateisomer of Si 21 reported by Pederson et al. ͓Phys. Rev. B 54, 2863 ͑1996͔͒.

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Section: Basin-hopping Global Optimization Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Global geometry optimization of silicon clusters described by three empirical potentials

Yoo

Zeng

2003

The Journal of Chemical Physics

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“…This is because the bonding feature of the Si 5n H 10 (n is an integer) clusters is very similar to that of the infinite SWSNTs; namely, the coordination number of every Si atom (except those at the ends) is fourfold. Note that previous ab initio calculations have shown that small-sized silicon clusters tend to favor a higher coordination number than fourfold (22)(23)(24). Hence, without the hydrogen termination at the ends, the stacked-pentagon silicon clusters will be unstable.…”

mentioning

confidence: 98%

Metallic single-walled silicon nanotubes

Bai

Zeng²,

Tanaka³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

130

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Atomistic computer-simulation evidences are presented for the possible existence of one-dimensional silicon nanostructures: the square, pentagonal, and hexagonal single-walled silicon nanotubes (SWSNTs). The local geometric structure of the SWSNTs differs from the local tetrahedral structure of cubic diamond silicon, although the coordination number of atoms of the SWSNTs is still fourfold. Ab initio calculations show that the SWSNTs are locally stable in vacuum and have zero band gap, suggesting that the SWSNTs are possibly metals rather than wide-gap semiconductors.L ow-dimensional nanostructures are known to have properties that can be markedly different from their bulk counterparts. For example, as shown in a recent experiment (1), Ho and coworkers demonstrated atom-by-atom evolution of electronic band structure of 1D gold chain. For semiconductor nanostructures, when the carriers (electrons and holes) are confined to dimensions less than their de Bröglie wavelength (typically a few nanometers), quantum-mechanical size effects can emerge. The carrier confinement at the nanoscale can be in 0D (quantum dots), 1D (quantum wires), or 2D (quantum wells) (2). Indeed, the current interest in fabricating low-dimensional semiconductor nanostructures, coined as band-structure engineering, has largely relied on novel quantum-mechanical size effects.The crystalline structure of 3D bulk silicon is cubic diamond, similar to that of carbon diamond. However, unlike the carbon counterpart (3), a 1D single-walled silicon nanotube (SWSNT) has not been found in nature yet, largely because silicon prefers sp 3 bonds rather than sp 2 bonds (4). Indeed, silicon has been viewed as nontubular solid rather than tubular solid, similar to carbon and boron nitride. The cubic diamond silicon is known as a semiconductor with an energy band gap of 1.17 eV (1 eV ϭ 1.602 ϫ 10 Ϫ19 J). At high pressures, however, the cubic-diamondstructured silicon can undergo a phase transformation to highly coordinated (sixfold or above) metallic phases such as the ␤-tin and hexagonal closed-packed structures (5). To date, experimentally produced 1D-like nanostructures of silicon [e.g., porous silicon (6) and silicon nanowires (7-12)] all assume either the cubic diamond crystalline structure or the local structure of amorphous silicon. A commonly reported electronic property of the 1D silicon nanostructures is that they all have wider band gap than the cubic diamond silicon. Here we present atomistic computer-simulation evidences of three thinnest SWSNTs: the square, pentagonal, and hexagonal silicon nanotubes. The local geometric structure of these SWSNTs differs from that of cubic diamond silicon and the surface-passivated 1D silicon nanowires. It also differs from that of the carbon-nanotube-like ''hypothetical'' SWSNTs (4, 13-15), because the latter types of SWSNTs are composed of both sp 3 and sp 2 bonds. Moreover, ab initio quantum-mechanical calculations show that the present SWSNTs exhibit an entirely opposite trend in the band-gap change compared wi...

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“…It has been suggested that NPs within different size regimes must be treated differently. For example, non-monotonic variations in the melting point (T m ) of small (< 200 atoms) size-selected clusters have been observed, 9,10 and assigned to the interplay of electronic and geometric effects. 9 However, the relative contribution of such effects could not be separated.…”

Section: Introductionmentioning

confidence: 99%