Unusual Spin Exchanges Mediated by the Molecular Anion P2S64−: Theoretical Analyses of the Magnetic Ground States, Magnetic Anisotropy and Spin Exchanges of MPS3 (M = Mn, Fe, Co, Ni)

We examined the magnetic ground states, the preferred spin orientations and the spin exchanges of four layered phases MPS3 (M = Mn, Fe, Co, Ni) by first principles density functional theory plus onsite repulsion (DFT + U) calculations. The magnetic ground states predicted for MPS3 by DFT + U calculations using their optimized crystal structures are in agreement with experiment for M = Mn, Co and Ni, but not for FePS3. DFT + U calculations including spin-orbit coupling correctly predict the observed spin orientations for FePS3, CoPS3 and NiPS3, but not for MnPS3. Further analyses suggest that the ||z spin direction observed for the Mn2+ ions of MnPS3 is caused by the magnetic dipole–dipole interaction in its magnetic ground state. Noting that the spin exchanges are determined by the ligand p-orbital tails of magnetic orbitals, we formulated qualitative rules governing spin exchanges as the guidelines for discussing and estimating the spin exchanges of magnetic solids. Use of these rules allowed us to recognize several unusual exchanges of MPS3, which are mediated by the symmetry-adapted group orbitals of P2S64− and exhibit unusual features unknown from other types of spin exchanges.

Download Full-text

FIRST-PRINCIPLES STUDIES ON THE ELECTRONIC STRUCTURE OF LuPd2Si2

International Journal of Modern Physics B ◽

10.1142/s0217979209054466 ◽

2009 ◽

Vol 23 (32) ◽

pp. 5929-5934 ◽

Cited By ~ 1

Author(s):

T. JEONG

Keyword(s):

Band Structure ◽

First Principles ◽

Density Functional ◽

Electronic Band Structure ◽

Local Density ◽

Spin Orbit Coupling ◽

Electronic Band ◽

Functional Theory ◽

The Density Functional Theory ◽

Structure Scheme

The electronic band structure of LuPd 2 Si 2 was studied based on the density functional theory within local density approximation and fully relativistic schemes. The Lu 4f states are completely filled and have flat bands around -5.0 eV. The fully relativistic band structure scheme shows that spin–orbit coupling splits the 4f states into two manifolds, the 4f7/2 and the 4f5/2 multiplet.

Download Full-text

Ab Initio Electronic Structure Studies of CuO Multiferroics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.488-489.129 ◽

2012 ◽

Vol 488-489 ◽

pp. 129-132 ◽

Cited By ~ 3

Author(s):

C. Kanagaraj ◽

Baskaran Natesan

Keyword(s):

First Principles ◽

Density Functional ◽

Electronic Band Structure ◽

Metallic State ◽

Magnetic Ground State ◽

Electronic Band ◽

Functional Theory ◽

High Tc ◽

Band Structure Calculations ◽

Structure Calculations

We have performed detailed structural, electronic and magnetic properties of high - TC multiferroic CuO using first principles density functional theory. The total energy results revealed that AFM is the most stable magnetic ground state of CuO. The DOS and electronic band structure calculations show that in the absence of on-site Coulomb interaction (U), AFM structure of CuO heads to a metallic state. However, upon incorporating U in the calculations, a band gap of 1.2 eV is recovered. Furthermore, the Born effective charges calculated on Cu does not show any anomalous character.This suggests that the polarization seen in CuO could be attributed to the spin induced AFM ordering effect.

Download Full-text

First-Principles Calculations of the Structure and Magnetic Phases of FeAs2 Compound under Pressure

SPIN ◽

10.1142/s2010324718500169 ◽

2018 ◽

Vol 08 (04) ◽

pp. 1850016 ◽

Cited By ~ 1

Author(s):

O. Sebaa ◽

Y. Zaoui ◽

K. O. Obodo ◽

H. Bendaoud ◽

L. Beldi ◽

...

Keyword(s):

Phase Transition ◽

First Principles ◽

Density Functional ◽

Stable Phase ◽

Spin Orbit Coupling ◽

First Principles Calculations ◽

Generalized Gradient ◽

Electronic Density ◽

Functional Theory ◽

Spin Ordering

Understanding of different magnetic configurations for the FeAs2 iron pnictide compound is carried out using first-principles studies based on spin density functional theory (DFT) within the generalized gradient approximation (GGA), including the spin–orbit coupling (SOC). The calculated stable phase is in the marcasite (Pnnm) with nonmagnetic spin-ordering. We find that the FeAs2 compound in the nonmagnetic (NM) marcasite phase undergoes pressure-induced phase transition to the antiferromagnetic (AFM1) marcasite phase at 12[Formula: see text]GPa, then to the AFM CuAl2 ([Formula: see text]4/mcm) phase at 63[Formula: see text]GPa. The phase transition is also accompanied by semiconducting (marcasite phase) to metallic (CuAl2 phase) transition. The calculated electronic density of states profile shows the hybridization of the Fe-3[Formula: see text] and As-4[Formula: see text] orbitals plays an important role in determining the electronic and magnetic characters of this compound. The associated phase transition results in increased Fe-3d orbitals around the Fermi energy level.

Download Full-text

First-principles study on the electronic and magnetic properties of ThMnAsN and ThMnPN

Modern Physics Letters B ◽

10.1142/s0217984921505138 ◽

2021 ◽

Author(s):

Hongli Gu ◽

Yu Yao ◽

Qingfang Li ◽

X. G. Wan ◽

Jian Zhou

Keyword(s):

Monte Carlo ◽

Magnetic Properties ◽

First Principles ◽

Density Functional ◽

Magnetic Ground State ◽

Functional Theory ◽

Text Type ◽

Electronic And Magnetic Properties ◽

The Density Functional Theory ◽

Synthesized Materials

The ZrCuSiAs materials have many interesting physical properties and have been extensively studied in recent decades. Recently, two Mn-based ZrCuSiAs-type pnictides, i.e. ThMnAsN and ThMnPN, have been synthesized in the experiment, which shows the anti-ferromagnetic properties. Motived by the experiment, we here perform a comprehensive investigation on their elastic, electronic, and magnetic properties by the density functional theory and Monte Carlo simulations. Our calculations show that ThMnAsN and ThMnPN are both antiferromagnetic semiconductors. The magnetic ground state of both materials is the [Formula: see text]-type anti-ferromagnetism and their bandgaps are about 0.47 eV and 0.61 eV for ThMnAsN and ThMnPN, respectively. The Monte Carlo simulated Néel temperatures of ThMnAsN and ThMnPN are 57 K and 55 K, respectively. These results are well consistent with the experimental results. Our work not only reveals the physical essence of the two newly synthesized materials but also could help to the understanding of the magnetic behaviors of other ZrCuSiAs-type compounds.

Download Full-text

The elusive magnetic ground state of sodium superoxide (NaO2)

10.21203/rs.3.rs-756659/v1 ◽

2021 ◽

Author(s):

Sarajit Biswas ◽

Molly De Raychaudhury

Keyword(s):

Ground State ◽

First Principles ◽

Alternative Energy ◽

Density Functional ◽

Structural Phase ◽

Li Ion Batteries ◽

Structural Phase Transitions ◽

Magnetic Ground State ◽

Functional Theory ◽

Li Ion

Abstract An alternative energy storage solution to Li-ion batteries is a higher alkali metal superoxide, namely NaO2. It is well-known that the transport properties of this alkali superoxide are governed by the transfer of charge between O2 dimers. Although it goes through a plethora of structural phase transitions, its electronic and magnetic ground state remains shrouded. In this work, we perform first-principles density functional theory (DFT) calculations in order to understand the electronic structure, the source of the ‘unconventional’ magnetic properties and its effect on conductivity in Na superoxide. Finally, we explore the connection between magnetogyration and the magnetic ground state of NaO2 remaining undetected till date.

Download Full-text

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

10.26434/chemrxiv.5439880 ◽

2017 ◽

Author(s):

Lyudmyla Adamska ◽

Sridhar Sadasivam ◽

Jonathan J. Foley ◽

Pierre Darancet ◽

Sahar Sharifzadeh

Keyword(s):

First Principles ◽

Density Functional ◽

State Of The Art ◽

Transparent Electrode ◽

Visible Range ◽

Two Dimensional ◽

Transparent Conductor ◽

Many Body ◽

Functional Theory ◽

Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Download Full-text

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

10.26434/chemrxiv.8052218.v3 ◽

2019 ◽

Author(s):

Henrik Pedersen ◽

Björn Alling ◽

Hans Högberg ◽

Annop Ektarawong

Keyword(s):

Thin Films ◽

Thermodynamic Stability ◽

First Principles ◽

Thermal Equilibrium ◽

Density Functional ◽

Van Der Waals ◽

Chemical Vapor ◽

First Principles Calculations ◽

Functional Theory ◽

The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

Download Full-text

The Damping Term, from First Principles

10.1093/oso/9780198788669.003.0006 ◽

2017 ◽

Author(s):

Olle Eriksson ◽

Anders Bergman ◽

Lars Bergqvist ◽

Johan Hellsvik

Keyword(s):

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Spin Dynamics ◽

Damping Term ◽

Functional Theory ◽

Basic Principles ◽

Sham Equation ◽

Damping Parameter ◽

Simulation Cell

In the previous chapters we described the basic principles of density functional theory, gave examples of how accurate it is to describe static magnetic properties in general, and derived from this basis the master equation for atomistic spin-dynamics; the SLL (or SLLG) equation. However, one term was not described in these chapters, namely the damping parameter. This parameter is a crucial one in the SLL (or SLLG) equation, since it allows for energy and angular momentum to dissipate from the simulation cell. The damping parameter can be evaluated from density functional theory, and the Kohn-Sham equation, and it is possible to determine its value experimentally. This chapter covers in detail the theoretical aspects of how to calculate theoretically the damping parameter. Chapter 8 is focused, among other things, on the experimental detection of the damping, using ferromagnetic resonance.

Download Full-text

Site preference and atomic ordering in the ternary Rh5Ga2As: first-principles calculations

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2021-2019 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Nilanjan Roy ◽

Sucharita Giri ◽

Harshit ◽

Partha P. Jana

Keyword(s):

Total Energy ◽

First Principles ◽

Density Functional ◽

Structure Type ◽

Site Preference ◽

X Ray Diffraction ◽

Atomic Ordering ◽

Functional Theory ◽

The Stability ◽

Bonding Characteristics

Abstract The site preference and atomic ordering of the ternary Rh5Ga2As have been investigated using first-principles density functional theory (DFT). An interesting atomic ordering of two neighboring elements Ga and As reported in the structure of Rh5Ga2As by X-ray diffraction data only is confirmed by first-principles total-energy calculations. The previously reported experimental model with Ga/As ordering is indeed the most stable in the structure of Rh5Ga2As. The calculation detected that there is an obvious trend concerning the influence of the heteroatomic Rh–Ga/As contacts on the calculated total energy. Interestingly, the orderly distribution of As and Ga that is found in the binary GaAs (Zinc-blende structure type), retained to ternary Rh5Ga2As. The density of states (DOS) and Crystal Orbital Hamiltonian Population (COHP) are calculated to enlighten the stability and bonding characteristics in the structure of Rh5Ga2As. The bonding analysis also confirms that Rh–Ga/As short contacts are the major driving force towards the overall stability of the compound.

Download Full-text

Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

Physical Chemistry Chemical Physics ◽

10.1039/d0cp05234e ◽

2021 ◽

Author(s):

I. Yu. Sklyadneva ◽

Rolf Heid ◽

Pedro Miguel Echenique ◽

Evgueni Chulkov

Keyword(s):

Density Functional Theory ◽

Double Layer ◽

First Principles ◽

Linear Response ◽

Density Functional ◽

Single Layer ◽

Phonon Interaction ◽

Functional Theory ◽

Electron Phonon Interaction ◽

The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

Download Full-text