Ferromanyetik Manganez Selenyumun Elektronik Davranışı ve Mekaniksel Özellikleri Üzerine Teorik Bir Çalışma: AgMn2Se4

Abstract

Bu çalışmada Fd3 ̅m uzay grubu ve 227 uzay numarası ile yüz merkezli kübik yapıda kristalleşen ferromanyetik kalgospinel manganez bazlı selenidin (AgMn₂Se₄) elektronik davranışı ve mekanik özellikleri incelenmiştir. Tüm başlangıç hesaplamaları, spin polarizasyonu altında Genelleştirilmiş Gradient Yaklaşımı (GGY) ile gerçekleştirildi. Söz konusu kompozisyon için hesaplamaların sonuçları onun ferromanyetik doğasına işaret etmektedir çünkü bu bileşik bu manyetik düzende diğer manyetik fazlarda olduğundan daha düşük taban durumu enerjisine sahiptir. Enerjitik olarak en kararlı manyetik faz tespit edildikten sonra bu manyetik düzendeki elektronik davranış incelenmiştir. Bu bileşiğin spin polarizasyon altında gözlenen elektronik bant yapısı azınlık spin durumunda küçük bir bant aralığına (E_b = 0.09 eV) sahip olması nedeniyle bu selenid sistemin neredeyse yarı-metalik bir malzeme olduğunu göstermektedir. Ek olarak, elastik sabitlerden yararlanılarak mekaniksel kararlılık belirlenmiş ve bu sabitler kullanılarak bu bileşiğin mekaniksel özellikleri elde edilmiştir.

Keywords

• Yarı-metalik
• Ferromanyetik
• Yoğunluk Fonksiyonel Teorisi
• Kalgonit
• Mekaniksel Özellikler

A Theoretical Study on Electronic Behavior and Mechanical Properties of Ferromagnetic Manganese Selenide: AgMn2Se4

Abstract

In this study, the electronic behavior and mechanical properties of the ferromagnetic chalcospinel manganese-based selenide (AgMn2Se4) which crystallized in face centered cubic structure with space group Fd3 ̅m and space number 227, were investigated. All ab initio calculations were carried out by Generalized Gradient Approximation (GGA) under spin polarization. For this composition, three different type magnetic orders were considered to detect the most stable magnetic character. For the given composition, the results of the computations indicate its ferromagnetic nature since this compound has a lower ground state energy in this magnetic order than in other magnetic phases. After determining the most energetically stable magnetic phase, the electronic behavior in this magnetic arrangement was examined. The observed electronic band structure under spin polarization of this compound shows that this selenide system is almost half-metallic material due to having small band gap (Eg = 0.09 eV) in the minority spin state. In addition, the mechanical stability was determined with the help of elastic constants which were also employed to determine the mechanical characteristics of this compound.

Keywords

• Half-metallic
• Ferromagnet
• Density functional theory
• Chalcogenide
• mechanical properties

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