Crystallographic Analysis of Structural Changes in Cubic Crystals

Nakagawa, Sachiko

doi:10.1143/jpsj.76.034603

Cited by 15 publications

(24 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We used a crystallographic analysis technique that we call PM (pixel mapping) [19,21]. Based on the crystallographic database for many inorganic crystals [22], PM describes the crystal structure of 24 prototype cubic crystals belonging to the space groups #195#230.…”

Section: Identification Of Phasementioning

confidence: 99%

“…Based on the crystallographic database for many inorganic crystals [22], PM describes the crystal structure of 24 prototype cubic crystals belonging to the space groups #195#230. A type IIa diamond belongs to a zincblende-type crystals as well as cases (Si, Ge, C, and many III-V compounds), where a common algebraic rule is used for those crystals in the same prototype group [19,21]. In the PM method, the entire space of a cubic crystal is segmented into small pixels with an address given by a set of integers (l, m, n), which has many advantages to identify various types of crystalline defects [19], if compared to ordinary description using real coordinates (x, y, z).…”

Section: Identification Of Phasementioning

confidence: 99%

See 1 more Smart Citation

The Phase Transition during Post Annealing

Nakagawa¹

2016

JPSA

View full text Add to dashboard Cite

Abstract:We have studied why PA (post-annealing) takes a long time to restore damaged crystallinity, which corresponds to repeat 10 10 times of lattice vibrations. Using a MD (molecular dynamics) simulation, we monitored the time-series of the LRO (long-range order) parameter as LRO pattern, in the case of a type IIa diamond, from the beginning of ion impact by a sub-keV N 2 beam implantation to a few nanoseconds, i.e., close to the feasible time limit for MD simulations. Due to the ion impact, the LRO parameter changed gradually from "LRO = 1" (crystal) to "LRO = 0" (amorphous), showing the so-called critical slowing-down phenomenon. However, since PA was started the LRO pattern was not unique. The LRO patterns were grouped into more than three types of phases and the transition between them was also found. From the viewpoint of statistical dynamics, such chaotic variations in the LRO pattern may present that the system is a GCM (globally coupled map) of a complex system in a closed system. A GCM composed of coupled oscillators develops slowly to exhibit several different phases or 'chaotic itinerancy' over time. Therefore, the long duration required for PA may be attributable to the nature of a complex system.

show abstract

Section: Identification Of Phasementioning

confidence: 99%

Section: Identification Of Phasementioning

confidence: 99%

The Phase Transition during Post Annealing

Nakagawa¹

2016

JPSA

View full text Add to dashboard Cite

show abstract

“…The issues are not only the nature of defect structures, their shape and their concentration, but also how they appear and disappear. In this paper we show how pixel mapping (PM) [1][2][3] has solved difficult issues of identification of defects in atomic coordinate files from numerical calculations of crystals.…”

Section: Introductionmentioning

confidence: 99%

“…For example, fluorite (CaF 2 ) belongs to the system n j = 4. The address of the pixels containing Ca atoms satisfies the condition mod (l + m + n, 4) = 0 for all three even integers (l, m, n), while that for the other F atoms satisfies another condition, mod (l + m + n, 4) = 1 or 3, for all three odd integers (l, m, n) [2]. For all 24 prototype crystals, we tabulated those algebraic rules in the PM Table as fingerprints of the occupied pixels.…”

mentioning

confidence: 99%

“…Therefore, from the address of a pixel in a prototype crystal, we can easily identify whether the pixel represents a vacancy or not, or if instead it contains a regular atom, an interstitial, or an antisite atom. Furthermore, the PM can predict the metastable site as being a preferable position for a migrating atom [2]. This is because with respect to the potential field, the PM assumes that each pixel is within a ligand field formed by the surrounding atoms.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Coarse‐grained analysis of crystalline defects caused by ion beam irradiation: The PM (pixel mapping) method

Nakagawa

2011

Electrical Engineering Japan

View full text Add to dashboard Cite

SUMMARYWe have proposed a numerical methodology called the pixel mapping (PM) method which is based on crystallography. The PM method can characterize various types of defects in 24 prototype crystals listed in the Strukturbericht database. It identifies point defects, linear defects, planar defects (including antiphase domains in compound crystals), and also structure change (including amorphization). The long-range order (LRO) parameter has been defined as a set of LRO components for each prototype. A further advantage of the PM method results from its coarse-grained viewpoint. This allows us to specify the Miller index of a planar defect with the areal density or crystallographic direction of a linear defect. Using PM we found a tetrahedral antisite cluster, (C Si (Si C ) 4 ), in 3C-SiC due to ion irradiation. The bonding directions from the central to the surrounding atoms were all in the <111> direction. We examined the reason why such a cluster was formed. Whenever this type of cluster was formed, collapse of LRO preceded, where large numbers of complexes of antisitesvacancy pairs emerged.

show abstract

Capillary electrophoresis of natural products: Highlights of the last five years (2006–2010)

2011

View full text Add to dashboard Cite

An extensive search of the published research and review articles indicated a growing number of works that employed electroseparation techniques. Capillary zone electrophoresis (CZE) and electrokinetic chromatography (EKC), in particular, were found to be popular for the analyses of natural products. This review outlines the important developments in this field over the years, especially during the 2006-2010 period. An overview of the natural product applications such as pharmaceuticals/herbal products, fingerprinting and quality control, food and food contaminants, and toxicological compounds of interest to forensics were presented. Important areas of detection strategies, microchips, sample preconcentration, and chiral separations were also discussed. Hence, quick information was provided on the researches already undertaken and the possibilities of unexplored areas. In addition, fundamental concepts for the understanding of CZE and EKC and their suitability for natural products analyses were briefly discussed.

show abstract

Crystallographic Analysis of Structural Changes in Cubic Crystals

Cited by 15 publications

References 18 publications

The Phase Transition during Post Annealing

The Phase Transition during Post Annealing

Coarse‐grained analysis of crystalline defects caused by ion beam irradiation: The PM (pixel mapping) method

Capillary electrophoresis of natural products: Highlights of the last five years (2006–2010)

Contact Info

Product

Resources

About