LnAuSb (Ln=La, Ce, Pr) bileşiklerinin fiziksel özelliklerinin teorik incelenmesi
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Tarih
2019
Yazarlar
Dergi Başlığı
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Cilt Başlığı
Yayıncı
Aksaray Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu tez çalışmasında LaAuSb, CeAuSb ve PrAuSb bileşikleri kuramsal olarak incelenmiştir. Bu bileşiklerin hekzagonal yapıda (uzay grubu 194, P63/mmc) kristal oluşturduğu bilinmektedir. Bileşiklerin yapısal, elektronik ve titreşimsel özellikleri hesaplanarak, elde edilen sonuçlar mevcut deneysel verilerle karşılaştırıldı. Deneysel olarak elde edilmesi güç ve masraflı olan fiziksel özellikler de ortaya çıkartıldı. Hesaplanan elektronik band yapılarından bu bileşiklerin metalik karakter sergiledikleri belirlendi. Ayrıca yük yoğunlukları yorumlanarak bağ yapıları hakkında ayrıntılı bilgi verildi. Bileşiklerin ikinci dereceden elastik sabitleri hesaplandı ve mekanik kararlılık şartlarını sağladıkları görüldü. Bu sabitler kullanılarak malzemelerin polikristal özellikleri (hacim, kesme, gerilme modülleri, Poisson oranı, Debye sıcaklığı, ortam ses hızları) ve yönelime bağlılıkları hakkında ayrıntılı inceleme yapıldı. Bu bileşiklerin genel olarak yumuşak ve esnek karakter sergiledikleri görüldü. Ayrıca, incelenen bileşiklerin fonon dağılımları ve fonon durum yoğunlukları, süper hücre ve yoğunluk fonksiyoneli pertürbasyon teorisi kullanılarak elde edildi. Malzemelerin titreşimsel olarak kararlı oldukları görüldü.
In this thesis, LaAuSb, CeAuSb and PrAuSb compounds were examined theoretically. These compounds are known to form crystalline in hexagonal (space group no: 194, P63/mmc). The obtained results by calculating the structural, electronic and vibrational properties of the compounds were compared with the available experimental data. Some physical properties, experimentally difficult to obtain and costly, were also released. From the electronic band structure calculations, it was determined that these compounds had metallic character. In addition, charge densities were interpreted and detailed information was given about bond structures. The second order elastic constants of the compounds were calculated and found to be lay down mechanical stability conditions. These constants were used to evaluate the polycrystalline properties (volume, shear, Young modules, Poisson’s ratio, Debye temperature, ambient sound velocities) and their anisotropy of the materials. It was determined that these compounds show soft and ductile nature. Also, the phonon distributions and phonon density of states of the compounds were visualized by supercell approximation and density functional perturbation theory. All considered materials were found vibrationally stable.
In this thesis, LaAuSb, CeAuSb and PrAuSb compounds were examined theoretically. These compounds are known to form crystalline in hexagonal (space group no: 194, P63/mmc). The obtained results by calculating the structural, electronic and vibrational properties of the compounds were compared with the available experimental data. Some physical properties, experimentally difficult to obtain and costly, were also released. From the electronic band structure calculations, it was determined that these compounds had metallic character. In addition, charge densities were interpreted and detailed information was given about bond structures. The second order elastic constants of the compounds were calculated and found to be lay down mechanical stability conditions. These constants were used to evaluate the polycrystalline properties (volume, shear, Young modules, Poisson’s ratio, Debye temperature, ambient sound velocities) and their anisotropy of the materials. It was determined that these compounds show soft and ductile nature. Also, the phonon distributions and phonon density of states of the compounds were visualized by supercell approximation and density functional perturbation theory. All considered materials were found vibrationally stable.
Açıklama
Anahtar Kelimeler
LaAuSb, CeAuSb, PrAuSb, Yapısal Özellikler, Mekanik Kararlılık, Titreşimsel Özellikler, Structural Properties, Mechanical Stability
