STUDY OF ELECTRONIC AND MAGNETIC PROPERTIES OF (LAO)MNAS AND (LAO0.875F0.125)MNAS USING DENSITY FUNCTIONAL METHOD

• Main Author: Prince Lubis, Tio
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/53700
• Institution: Institut Teknologi Bandung

Research on the characteristics or properties of semiconductors is carried out to continuously improve the functionality of the material to answer human needs. In this study we characterized (LaO)MnAs and (LaO0.875F0.125)MnAs using the Density Functional Theory (DFT) method based on generalized gradient approximation (GGA) and GGA + U. DFT is an approach used to find solutions to quantum behavior of atoms and molecules by considering a wave function with electron density. In this study, the DFT method was carried out using Quantum ESPRESSO software. With GGA, the bandgap value of (LaO)MnAs was 0.5842 eV, far below the experimental value, 1.4 eV, and was antiferromagnetic with a magnetic moment 3.98 ?B/Mn. Giving Hubbard's correction increased the bandgap value to 1.32 eV (U = 10 eV), but resulted in a crystal structure that was far from the experimental results. The calculation of the energy band structure (LaO0.875F0.125)MnAs shows the conduction band moves closer to the valence band until it passes the fermi energy with a bandgap of 0.837 eV due to the addition of one free electron by the F dopant and the magnetic moment value was 4.22 ?B/Mn . These results indicate that the functional exchange correlation GGA is not good enough for modeling the MnAs(LaO) system and the best Hubbard's correction based on the calculation of the parameter structure is when U = 1 eV.