Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 1Citation - Scopus: 1Pressure-Induced Phase Transformations in Amorphous Arsenic(Elsevier Science Bv, 2016-04) Durandurdu, MuratThe atomic structure of amorphous arsenic and its response to high pressure are explored using a constant pressure ab initio molecular dynamics technique. Different analyzing techniques reveal that amorphous arsenic has a local structure close to that of the crystalline phase. The model also presents some twofold and fourfold coordination defects. The existence of a possible amorphous to amorphous phase transition for arsenic is proposed on the bases of the observation of a gradual coordination increase with the application of pressure. Further compression of the amorphous state yields a transformation into a simple cubic crystal. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Liquid and Amorphous States of Boron Subarsenide(Wiley, 2019-08-13) Durandurdu, MuratAb initio molecular dynamics simulations are executed to probe the short-range order and the electrical features of the liquid and amorphous boron subarsenide (B12As2). A drastic volume swelling of similar to 40% is witnessed for the liquid state, relative to the crystal. The density of the melt is found to be close to that of liquid boron. As the temperature applied is gradually decreased, the volume progressively decreases and a glass-transition zone at around 1400 K is observed. About 14% volume expansion is perceived for the amorphous phase. Due to the drastic density (volume) difference between the liquid and amorphous forms, their atomic structure is found to be different from each other. In the liquid phase at 2500 K, the mean coordination number (CN) of B and As atoms is 4.4 and 2.5, correspondingly. During the solidification process, both average CNs steadily increase and reach values of 5.5 (B-atom) and 4.14 (As-atom) at 300 K. The pentagonal pyramid-like motifs barely survive at 2500 K but during the quenching process they develop progressively and some of which lead to the formation of B-12 clusters. In the amorphous state, the chain-like and A7-like As-As clusters are observed. Nonetheless, the noncrystalline state is proposed to be partially similar to the crystalline structure. The liquid state shows a metallic character while the amorphous form presents a semiconducting nature having an energy band gap much smaller than that of the crystalline phase.