Dataset on density functional theory investigation of ternary Heusler alloys

This paper contains data and results from Density Functional Theory (DFT) investigation of 423 distinct X2YZ ternary full Heusler alloys, where X and Y represent elements from the D-block of the periodic table and Z signifies element from main group. The study encompasses both “regular” and “inverse” Heusler phases of these alloys for a total of 846 potential materials. For each specific alloy and each phase, a range of information is provided including total energy, formation energy, lattice constant, total and site-specific magnetic moments, spin polarization as well as total and projected density of electronic states. The aim of creating this dataset is to provide fundamental theoretical insights into ternary X2YZ Heusler alloys for further theoretical and experimental analysis.

The first principal calculations were performed using Quantum Espresso [1] (Version 6.8) simulation package on X 2 YZ Heusler alloys.The total energy of each alloy was calculated as a function of the calculated lattice parameter.A Self-Consistent Field (SCF) calculation followed by a non-SCF calculation were performed to get the Density of States (DOS) and projected Density of States (PDOS) of each of these alloys.Spin Polarization ( P F ) was calculated by using the density of states (DOS) of spin-up and -down electrons at Fermi energy ( E F ). Data Source Institution: The University of Alabama Location City, State: Tuscaloosa, Alabama Country: United States of America Data accessibility DOI: 10.17632/by523ywzs9.3Direct URL to data: https://data.mendeley.com/datasets/by523ywzs9/3

Value of the Data
• This dataset will provide fundamental information about 423 ternary Heusler alloys in their regular ( L2 1 ) and inverse ( XA ) Heusler phases, for a total of 846 distinct alloys calculated.Structure, magnetic properties, and spin polarization values are provided as a launching point for future studies.• This wide-scale database will serve as a valuable screening tool for identifying promising candidates and conducting thorough and comprehensive studies on ternary Heusler alloys.• The dataset is also useful for machine learning studies of structure, phase stability, and electronic and magnetic properties of alloy systems.

Objective
Heusler alloys have attracted substantial attention within the research community due to their potential applications in fields such as spintronics [2] and thermo-electric devices [3] .Considerable focus is now being paid to identify novel candidates with advanced properties and their possible application in various fields.The enclosed comprehensive dataset of Heusler alloys, including structure properties and stability, magnetic structure and spin polarization, and electronic structure via density of states calculations, is valuable for researchers seeking to identify novel candidates and more quickly progress to subsequent in-depth theoretical and experimental exploration.

Data Description
Heusler compounds first attracted interest when Cu 2 MnAl was discovered by German scientist Fritz Heusler in 1903 [4] .This remarkable face-centered cubic compound exhibited ferromagnetic properties although none of its constituent elements possessed inherent ferromagnetism.Motivated by this discovery, researchers worldwide have identified over a thousand Heusler alloys and their relatives within the past century and the quest for more continues to this day.To facilitate this quest, we have generated collections of X 2 YZ Heusler alloys.This dataset stands out as one of the few comprehensive databases accessible for researchers in this field [5] , offering a complementary source of data alongside the well-known Open Quantum Materials Datasets (OQMD) [ 6 , 7 ], Material Projects (MP) [8] and Automatic-FLOW for Materials Discovery (AFlow) Fig. 1.Orthogonal element choice for density functional theory calculations.[9] .Data on Materials Project (MP) are collected from two sources: (1) high-throughput calculations on supercomputing clusters; (2) academic community using MPContribs [10] .Data collected with (1) came from calculations performed using VASP [11] , a well-reputed package that uses a full-potential method.However, self-consistent calculations (SCF) of many Heusler compounds and non-self-consistent calculations (NSCF) prior to DOS calculations were performed with a low k-point grid.Data for MP, OQMD and AFLOW were uploaded via Application Programming Interface (API) [12] from a supportive academic community comprise of many experienced researchers.However, the lack of a consistency in computation methods and parameters across over a thousand Heusler compounds makes it very difficult to create models of generalized behavior of Heuslers.
Moreover, MP, OQMD and AFLOW websites contain only a subset of Heusler compounds, many of which are included in our dataset.For example, the X 2 VAl Heusler series featured in this manuscript, with X-sites choices Sc, Cu, Y, Nb, Mo, Hf, Ta and W, are not included in the MP website.
Table 1 summarizes the data collected on a series of X 2 VAl ( X = Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb.Mo, Hf, TA, W) full (L2 1 ) and inverse (XA) Heusler alloys.The total energy of the system can be conceptualized as the energy required to construct the system at absolute zero temperature by assembling single atoms of constituting elements.The calculations of density of states show that Y 2 VAl, Zr 2 VAl and Hf 2 VAl are half metals in their inverse Heusler phases.Fig. 2 represents the total and atom-resolved density of states of X 2 VAl alloy series in their L2 1 and XA phases.
The total density of states (DOS) and site-specific projected density of states (pDOS) of X 2 VAl where X is one of the fifteen 3d elements presented in Table 1 are shown in Fig. 2 .The L2 1 phases are displayed on the left and the XA phases are on the right side of the figure.The X -  Where E T is the total energy for given volume V, B 0 is the bulk modulus at the equilibrium volume V 0 and B 0 is the pressure derivative of the bulk modulus at the equilibrium volume V 0 .The ground state lattice structure was obtained by relaxing the system using conjugate-gradient method which allows the cell shape and volume change freely until it finds the ground-state.All alloys were considered spin-polarized and a small non-zero starting magnetization value was set for all atomic types in the alloy.Pseudopotentials from Quantum Espresso PSLibrary (generated by A. Dal Corso) [13] were used in our calculations and are included in the Supplementary Material.The formation energy of the alloys is calculated by subtracting the energy corresponding to individual element from the calculated total energy ( E total ) of the alloy.The value of E total was obtained from the ground state self-consistent (SCF) calculations.
For elemental calculations, the calculation steps and convergence parameters were the same as what we used for alloy calculations.The known ground state structure was used for all elements, e.g., simple hexagonal structure for Scandium, Hafnium, Zirconium, bcc structure for Chromium, Iron, fcc structure for Copper, Silicon, Aluminum, etc.A non-SCF calculation was performed after the self-consistent field (SCF) calculation to get the density of states (DOS) and projected density of states (pDOS) of each of these alloys.Spin Polarization ( P F ) was calculated by using the density of states (DOS) at the Fermi energy in spin-up and -down states.
The calculations were performed without considering the effect of spin-orbit coupling.

Limitations
None.

Ethics Statement
The proposed data does not involve any human subjects, animal experiments, or data collected from social media platforms.

Table 1
A list of lattice constant, energy, magnetic moment, and spin polarization of X 2 VAl Heusler alloy in their regular ( L2 1 ) and inverse ( XA ) Heusler phases.Total density of states (DOS) and projected density of states (pDOS) of X 2 VAl Heusler alloys ( X = Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Hf, Ta, W).