scholarly journals Magnetic ground state and electron-doping tuning of Curie temperature in Fe3GeTe2 : First-principles studies

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
Zhen-Xiong Shen ◽  
Xiangyan Bo ◽  
Kun Cao ◽  
Xiangang Wan ◽  
Lixin He
Keyword(s):  
Curie Temperature ◽  
Ground State ◽  
First Principles ◽  
Magnetic Ground State ◽  
Electron Doping

Importance of Thermally Induced Magnetic Excitations in First-Principles Simulations of Elastic Properties of Transition Metal Alloys

2012 ◽  
Vol 190 ◽  
pp. 291-294
Author(s):  
Igor A. Abrikosov ◽  
Marcus Ekholm ◽  
Alena V. Ponomareva ◽  
Svetlana A. Barannikova
Keyword(s):  
Transition Metal ◽  
Elastic Properties ◽  
Ground State ◽  
First Principles ◽  
Magnetic Moments ◽  
Metal Alloys ◽  
Face Centered Cubic ◽  
Magnetic Ground State ◽  
Magnetic Excitations ◽  
Transition Metal Alloys

We demonstrate the importance of accounting for the complex magnetic ground state and finite temperature magnetic excitations in theoretical simulations of structural and elastic properties of transition metal alloys. Considering Fe72Cr16Ni12face centered cubic (fcc) alloy, we compare results of first-principles calculations carried out for ferromagnetic and non-magnetic states, as well as for the state with disordered local moments. We show that the latter gives much more accurate description of the elastic properties for paramagnetic alloys. We carry out a determination of the magnetic ground state for fcc Fe-Mn alloys, considering collinear, as well as non-collinear states, and show the sensitively of structural and elastic properties in this system to the detailed alignment between magnetic moments. We therefore conclude that it is essential to develop accurate models of the magnetic state for the predictive description of properties of transition metal alloys.

scholarly journals First-principles study of magnetic ground state of quantum paraelectric EuTiO3 material

2014 ◽  
Vol 63 (8) ◽  
pp. 087502
Author(s):  
Li Cheng-Di ◽  
Zhao Jing-Long ◽  
Zhong Chong-Gui ◽  
Dong Zheng-Chao ◽  
Fang Jing-Huai
Keyword(s):  
Ground State ◽  
First Principles ◽  
Magnetic Ground State ◽  
First Principles Study ◽  
Quantum Paraelectric

scholarly journals The first-principles investigations on magnetic ground-state in Sm-doped phenanthrene

AIP Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 055704 ◽  
Author(s):  
Jia-Xing Han ◽  
Guo-Hua Zhong ◽  
Xiao-Hui Wang ◽  
Xiao-Jia Chen ◽  
Hai-Qing Lin
Keyword(s):  
Ground State ◽  
First Principles ◽  
Magnetic Ground State

scholarly journals First-principles investigation of transport and magnetism

2021 ◽  
Author(s):  
◽  
Aditya Putatunda
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Magnetic Energy ◽  
Band Model ◽  
Magnetic Ground State ◽  
Critical Material ◽  
Theoretical Concepts ◽  
Quantum Critical

Study of the quantum mechanical nature of a material provides invaluable understanding of its underlying mechanisms governing their fascinating novel properties. Density functional based first-principles methods provide us with the necessary tools to approximate the Schrodinger's equation for many-electron periodic solids. Starting from the atomic position of their constituent atoms, using one of the most accurate methods of all-electron calculations, here in this thesis, I present my investigations of several such different materials in light of these novel phenomena. In the first chapter, I have discussed the basics of this tool and other theoretical concepts that work in the background in order to obtain reliant and consistent results. The results on each of these materials have been arranged around the following six chapters. The second chapter, in its two sections, I demonstrated these methods via two materials: a) the widely known industrial compound TiO2 where I addressed the long standing theory versus experiment disparity of the energy ordering of its two most used polymorphs. Our results, like most of the previous theoretical studies gave anatase as its ground state. In the next section, I investigated the recently synthesized layered monoclinic material: NaSbSe2. The results on its superior electronic and transport property shows its potential as a thermoelectric (TE) candidate. The investigation of TE properties in next chapter focusses on the Lorenz number where a certain widely used prescription for its approximation has been closely examined. Comparing against our first-principles based transport results on few well-known TEs as well as the ideal single parabolic band model, I found that for some materials the prescription works well within acceptable deviations. However, for TEs with complex band structure the deviations are too big which suggests precaution to its use since efficient TEs are often marked by such complex electronic structures only. The following chapters explore magnetism. Starting with the discussion of the pervoskite compound MnSeO3, we found our results to be predicting its true magnetic ground state order. The study of its energetics and electronic structure, in comparison to its non-magnetic analogue ZnSeO3, its magnetic nature was determined to be of local moment nature. Showing unconventional structural properties for a pervoskite compound, doping and spin-wave dispersion investigations will probably be useful. In the next two chapters, I focus on the novel material Sr3Ru2O7. Widely considered as a classic quantum critical material, I discuss why it is important to understand the nature of fluctuations associated with its quantum critical properties. For this purpose, it is important to know the low-energy metastable states in competition with its ground state. The first-principles investigation based survey yielded the striped E-type antiferromagnetic state that lies closest to the ground state. The magnetic-energy ordering in combination to its electronic structure properties, e.g. the density of states suggest its magnetism to be of itinerant nature. My results on the electronic transport indicates that only this striped E-type ordered state carries a distinct anisotropy among its in-plane conductivity components. This result is particularly important since the material Sr3Ru2O7 is experimentally known to display a similar transport anisotropy of the same order under specific magnetic field.

scholarly journals The elusive magnetic ground state of sodium superoxide (NaO2)

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.

scholarly journals Magnetic Behavior in TiS3 Nanoribbon

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3501
Author(s):  
Shengqiang Lai ◽  
Yongping Du
Keyword(s):  
Phase Transition ◽  
Ground State ◽  
First Principles ◽  
Tensile Strain ◽  
Magnetic Behavior ◽  
Strain Response ◽  
First Principles Calculations ◽  
Magnetic Ground State ◽  
Promising Candidate ◽  
Half Metal

The electronic structure, magnetic properties and strain response of N-a-TiS3 nanoribbons are investigated by first-principles calculations. We find that the magnetic ground state is strongly dependent on width of a-TiS3. When N equals an odd number the ground state is a ferromagnetic (FM) metal, meanwhile, when N equals an even number the ground state is an anti-ferromagnetic (AFM) metal. More interestingly, a tensile strain as large as 6% can tune the 9-a-TiS3 nanoribbon from a FM metal to a half metal. A 4% tensile strain also causes a phase transition from AFM to FM ground state for 10-a-TiS3 nanoribbon. Our findings show that N-a-TiS3 is a promising candidate for spintronic and electronic applications.

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