DFT-based investigation of electronic-structure, magnetic and thermoelectric properties of Dy₂CoMnO₆ double perovskite

Abstract

Abstract The density functional theory as a computational approach was used to explore the ferrimagnetic semiconducting behavior of Dy 2 CoMnO 6 double perovskite compound in both spin-up and spin-down directions. Thermodynamic stability was confirmed in a wide pressure range set to 30 GPa. Both scalar and full relativistic calculations are used to estimate the spin–orbit effect. The topological distribution of the charge density and the net effective charge of each atom are studied based on the Quantum Theory of Atoms in Molecules (QTAIM) as implemented in Bader code, Besides this, the different QTAIM atomic basins descriptors such as electron density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">ρ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="bold-italic">b</mml:mi> </mml:mrow> </mml:msub> <mml:mo>,</mml:mo> </mml:math> Laplacian of the electron density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">∇</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">ρ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="bold-italic">b</mml:mi> </mml:mrow> </mml:msub> <mml:mo>,</mml:mo> </mml:math> potential electronic energy density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="bold-italic">b</mml:mi> </mml:mrow> </mml:msub> <mml:mo>,</mml:mo> </mml:math> kinetic electronic energy density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">G</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="bold-italic">b</mml:mi> </mml:mrow> </mml:msub> <mml:mspace width="0.25em"/> </mml:math> and density of the total electronic energy <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">H</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="bold-italic">b</mml:mi> </mml:mrow> </mml:msub> <mml:mspace width="0.25em"/> </mml:math> at bond critical points (BCPs) are estimated using CRITIC2 software where the ionic type for Dy-O, Co-O, and Mn-O bonds are evaluated. Holes and electrons have different effective masses, their thermoelectric properties appear high figure of merit (ZT) exceeding 0.5 for temperatures greater than 500 K in the negative chemical potential region, suggesting that doping with holes might be more favorable for thermoelectric efficiency than doping with electrons.