TY - GEN

T1 - Modeling of full-Heusler alloys within tight-binding approximation

T2 - 2nd International Symposium on Current Progress in Mathematics and Sciences 2016, ISCPMS 2016

AU - Azhar, A.

AU - Majidi, Muhammad Aziz

AU - Nanto, D.

PY - 2017/7/10

Y1 - 2017/7/10

N2 - Heusler alloys have been known for about a century, and predictions of magnetic moment values using Slater-Pauling rule have been successful for many such materials. However, such a simple counting rule has been found not to always work for all Heusler alloys. For instance, Fe2CuAl has been found to have magnetic moment of 3.30 μB per formula unit although the Slater-Pauling rule suggests the value of 2 μB. On the other hand, a recent experiment shows that a non-stoichiometric Heusler compound Fe2Mn0.5Cu0.5Al possesses magnetic moment of ~4 μB, closer to the Slater-Pauling prediction for the stoichiometric compound. Such discrepancies signify that the theory to predict the magnetic moment of Heusler alloys in general is still far from being complete. Motivated by this issue, we propose to do a theoretical study on a full-Heusler alloy Fe2MnAl to understand the formation of magnetic moment microscopically. We model the system by constructing a density-functional-theory-based tight-binding Hamiltonian and incorporating Hubbard repulsive as well as spin-spin interactions for the electrons occupying the d-orbitals. Then, we solve the model using Green's function approach, and treat the interaction terms within the mean-field approximation. At this stage, we aim to formulate the computational algorithm for the overall calculation process. Our final goal is to compute the total magnetic moment per unit cell of this system and compare it with the experimental data.

AB - Heusler alloys have been known for about a century, and predictions of magnetic moment values using Slater-Pauling rule have been successful for many such materials. However, such a simple counting rule has been found not to always work for all Heusler alloys. For instance, Fe2CuAl has been found to have magnetic moment of 3.30 μB per formula unit although the Slater-Pauling rule suggests the value of 2 μB. On the other hand, a recent experiment shows that a non-stoichiometric Heusler compound Fe2Mn0.5Cu0.5Al possesses magnetic moment of ~4 μB, closer to the Slater-Pauling prediction for the stoichiometric compound. Such discrepancies signify that the theory to predict the magnetic moment of Heusler alloys in general is still far from being complete. Motivated by this issue, we propose to do a theoretical study on a full-Heusler alloy Fe2MnAl to understand the formation of magnetic moment microscopically. We model the system by constructing a density-functional-theory-based tight-binding Hamiltonian and incorporating Hubbard repulsive as well as spin-spin interactions for the electrons occupying the d-orbitals. Then, we solve the model using Green's function approach, and treat the interaction terms within the mean-field approximation. At this stage, we aim to formulate the computational algorithm for the overall calculation process. Our final goal is to compute the total magnetic moment per unit cell of this system and compare it with the experimental data.

UR - http://www.scopus.com/inward/record.url?scp=85026215393&partnerID=8YFLogxK

U2 - 10.1063/1.4991144

DO - 10.1063/1.4991144

M3 - Conference contribution

AN - SCOPUS:85026215393

T3 - AIP Conference Proceedings

BT - International Symposium on Current Progress in Mathematics and Sciences 2016, ISCPMS 2016

A2 - Sugeng, Kiki Ariyanti

A2 - Triyono, Djoko

A2 - Mart, Terry

PB - American Institute of Physics Inc.

Y2 - 1 November 2016 through 2 November 2016

ER -