Date of Graduation

8-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Microelectronics-Photonics (PhD)

Degree Level

Graduate

Department

Microelectronics-Photonics

Advisor/Mentor

Manasreh, Bothina H.

Committee Member

Manasreh, Omar O.

Second Committee Member

Ware, Morgan E.

Third Committee Member

Churchill, Hugh O.H.

Fourth Committee Member

Leftwich, Matthew B.

Keywords

AIMD simulations; Chalcogenides; Lattice anharmonicity; Quaternary Heusler alloys; SCP theory; Thermoelectric

Abstract

The structural, dynamical, electronic, and thermoelectric properties of rock-salt and wurtzite Cd1-xZnxO alloys, VTiRhZ (Al, Ga, In, Si, Ge, Sn) and ZrTiRhZ (Ge, Sn) quaternary Heusler alloys (QHAs) were investigated using density functional theory (DFT) and semi-classical Boltzmann transport theory. From these calculations, the alloys were identified as potential materials for future thermoelectric applications. Furthermore, the magnetic and spin-polarization properties of these QHAs were investigated. The total magnetic moments were found to be integer values for all QHAs. In addition, all studied QHAs except VTiRhAl possess a half-metallic behavior with a 100% spin-polarization. The half-metallic ferromagnetic behavior makes them promising materials for spintronic applications. Moreover, the influence of the lattice anharmonicity on the lattice thermal conductivity of InTe monolayer were studied using the standard Boltzmann transport equation (BTE) approach and the self-consistent phonon with Boltzmann transport equation (SCP + BTE). The SCP + BTE approach is believed to be more valid and accurate than the standard BTE approach in predicting the κ_l value. These investigations using the SCP + BTE approach show that InTe monolayer is promising for thermoelectric applications.

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