بررسي ويژگي‌هاي فيزيكي تك‌لايه‌هاي سولفيد پلاتين(PtS_2) و سولفيد قلع (SnS_2)

Investigation of the physical properties of Platinum sulfide (PtS_2) an‎d Tin sulfide (SnS_2)

فيزيك ماده چگال

In this research, we examine the density functional theory an‎d its application in studying the structural an‎d electronic properties of bulk an‎d monolayer PtS_2 an‎d SnS_2. First, the basic concepts of density functional theory an‎d the Kohn-Sham equations for solving the quantum equations of periodic systems are introduced. Then, the importance of exchange-correlation energy in this theory is explained, an‎d various approximations for calculating it, including the Local Density Approximation (LDA) an‎d the Generalized Gradient Approximation (GGA), are discussed. In the next section, the classical an‎d quantum Hall effects an‎d their relationship with the topology of materials are explained. This section focuses on the topological phases of materials an‎d the topological properties of materials, with an emphasis on the quantum Hall effect an‎d spin. Additionally, due to the importance of the Berry phase in topological ban‎d theory, analyses will be conducted on the topological changes in materials an‎d their effects. Subsequently, various studies on transition metal dichalcogenides, a class of two-dimensional materials, are reviewed. The structural properties, energy ban‎ds, an‎d density of states of these materials under pressure an‎d different conditions are analyzed. Moreover, the use of these materials in devices such as transistors an‎d solar cells is discussed. Finally, this thesis investigates the dynamic structure an‎d optical properties of bulk an‎d monolayer PtS_2 an‎d SnS_2, examining the effects of pressure on the optical an‎d elastic properties of these materials.

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