Electronic Structure of Monolayer FeSe on Si(001) from First Principles

The huge increase in the superconducting transition temperature of FeSe induced by an interface to SrTiO3 remains unexplained to date. However, there are numerous indications of the critical importance of specific features of the FeSe band topology in the vicinity of the Fermi surface. Here, we explore how the electronic structure of FeSe changes when located on another lattice matched substrate, namely a Si(001) surface, by first-principles calculations based on the density functional theory. We study non-magnetic (NM) and checkerboard anti-ferromagnetic (AFM) magnetic orders in FeSe and determine which interface arrangement is preferred. Our calculations reveal interesting effects of Si proximity on the FeSe band structure. Bands corresponding to hole pockets at the Γ point in NM FeSe are generally pushed down below the Fermi level, except for one band responsible for a small remaining hole pocket. Bands forming electron pockets centered at the M point of the Brillouin zone become less dispersive, and one of them is strongly hybridized with Si. We explain these changes by a redistribution of electrons between different Fe 3d orbitals rather than charge transfer to/from Si, and we also notice an associated loss of degeneracy between dxz and dyz orbitals.

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First Principles Calculations of Electronic Structure and Optical Properties of Cu-Doped SnS2

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.373-375.1965 ◽

2013 ◽

Vol 373-375 ◽

pp. 1965-1969

Author(s):

Kun Nan Qin ◽

Ling Zhi Zhao ◽

Yong Mei Liu ◽

Fang Fang Li ◽

Chao Yang Cui

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Optical Absorption Coefficient ◽

Impurity Level ◽

First Principles Calculations ◽

Absorption Region ◽

Functional Theory ◽

The Density Functional Theory

The electronic structure and optical properties of Cu-doped SnS2with Sn-substituted content of 0, 12.5 and 37.5 at.% were successfully calculated by the first principles plane-wave pseudopotentials based on the density functional theory. It is found that the intermediate belts appear near the Fermi level and the energy band gap becomes narrower after the doping of the Cu atoms. The absorption peaks show a remarkable redshift and the absorption region broadens relatively after introducing acceptor impurity level. When Sn atoms of 37.5 at% were substituted by Cu, the optical absorption coefficient is significantly improved in the frequency range below 5.58 eV and over 8.13 eV.

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First Principles Calculations of Atomic and Electronic Structure of TiAl3+- and TiAl2+-Doped YAlO3

Materials ◽

10.3390/ma14195589 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5589

Author(s):

Sergei Piskunov ◽

Aleksejs Gopejenko ◽

Vladimir Pankratov ◽

Inta Isakoviča ◽

Chong-Geng Ma ◽

...

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

Interatomic Distances ◽

Atomic Orbitals ◽

The Density Functional Theory ◽

F Center ◽

Atomic And Electronic Structure

In this paper, the density functional theory accompanied with linear combination of atomic orbitals (LCAO) method is applied to study the atomic and electronic structure of the Ti3+ and Ti2+ ions substituted for the host Al atom in orthorhombic Pbnm bulk YAlO3 crystals. The disordered crystalline structure of YAlO3 was modelled in a large supercell containing 160 atoms, allowing simulation of a substitutional dopant with a concentration of about 3%. In the case of the Ti2+-doped YAlO3, compensated F-center (oxygen vacancy with two trapped electrons) is inserted close to the Ti to make the unit cell neutral. Changes of the interatomic distances and angles between the chemical bonds in the defect-containing lattices were analyzed and quantified. The positions of various defect levels in the host band gap were determined.

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Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

Canadian Journal of Physics ◽

10.1139/p06-008 ◽

2006 ◽

Vol 84 (2) ◽

pp. 115-120 ◽

Cited By ~ 3

Author(s):

G Y Gao ◽

K L Yao ◽

Z L Liu

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Pseudopotential Calculations ◽

Correlation Potential ◽

Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

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First-principles study of static displacements in Fe-Pd magnetic shape-memory alloys

MRS Proceedings ◽

10.1557/proc-1200-g04-04 ◽

2009 ◽

Vol 1200 ◽

Cited By ~ 1

Author(s):

Markus E. Gruner

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Magnetic Shape Memory ◽

Magnetic Shape Memory Alloys ◽

Functional Theory ◽

Lennard Jones ◽

Theory Comparison

AbstractThis contribution reports static ionic displacements in ferromagnetic disordered Fe70Pd30 alloys obtained by relaxation of the ionic positions of a 108-atom supercell within the framework of density functional theory. Comparison with a simple statistical model based on Lennard-Jones pair interactions reveals that these displacements are significantly larger than can be explained by the different sizes of the elemental constituents. The discrepancies are presumably related to collective displacements of the Fe atoms. Corresponding distortions are experimentally observed for ordered Fe3Pt and predicted by first-principles calculations for all ordered Fe-rich L12 alloys with Ni group elements and originate from details of the electronic structure at the Fermi level.

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Electronic, optical and thermoelectric properties of Fe2ZrP compound determined via first-principles calculations

RSC Advances ◽

10.1039/c9ra04736k ◽

2019 ◽

Vol 9 (44) ◽

pp. 25900-25911 ◽

Cited By ~ 3

Author(s):

Esmaeil Pakizeh ◽

Jaafar Jalilian ◽

Mahnaz Mohammadi

Keyword(s):

Density Functional Theory ◽

Thermoelectric Properties ◽

First Principles ◽

Density Functional ◽

Transport Theory ◽

First Principles Calculations ◽

Boltzmann Transport ◽

Functional Theory ◽

Boltzmann Transport Theory ◽

The Density Functional Theory

In this study, based on the density functional theory and semi-classical Boltzmann transport theory, we investigated the structural, thermoelectric, optical and phononic properties of the Fe2ZrP compound.

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Effect of Defects on Spontaneous Polarization in Pure and Doped LiNbO3: First-Principles Calculations

Materials ◽

10.3390/ma12010100 ◽

2018 ◽

Vol 12 (1) ◽

pp. 100 ◽

Cited By ~ 5

Author(s):

Weiwei Wang ◽

Dahuai Zheng ◽

Mengyuan Hu ◽

Shahzad Saeed ◽

Hongde Liu ◽

...

Keyword(s):

Spontaneous Polarization ◽

First Principles ◽

Density Functional ◽

Lattice Distortion ◽

Stable Structure ◽

First Principles Calculations ◽

Functional Theory ◽

The Density Functional Theory ◽

Specific Configuration ◽

The Relationship

Numerous studies have indicated that intrinsic defects in lithium niobate (LN) dominate its physical properties. In an Nb-rich environment, the structure that consists of a niobium anti-site with four lithium vacancies is considered the most stable structure. Based on the density functional theory (DFT), the specific configuration of the four lithium vacancies of LN were explored. The results indicated the most stable structure consisted of two lithium vacancies as the first neighbors and the other two as the second nearest neighbors of Nb anti-site in pure LN, and a similar stable structure was found in the doped LN. We found that the defects dipole moment has no direct contribution to the crystal polarization. Spontaneous polarization is more likely due to the lattice distortion of the crystal. This was verified in the defects structure of Mg2+, Sc3+, and Zr4+ doped LN. The conclusion provides a new understanding about the relationship between defect clusters and crystal polarization.

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Ab initio study of optical and bulk properties of cesium lead halide perovskite solid solutions

Modern Physics Letters B ◽

10.1142/s021798491950386x ◽

2019 ◽

Vol 33 (31) ◽

pp. 1950386

Author(s):

Vladimir Saleev ◽

Alexandra Shipilova

Keyword(s):

Solid Solutions ◽

First Principles ◽

Disordered Systems ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

Bulk Properties ◽

The Density Functional Theory ◽

Halide Perovskite ◽

Lead Halide

The first-principles calculations of band gaps and bulk moduli of cesium lead halide perovskite solid solutions, [Formula: see text] and [Formula: see text], are performed at the level of general gradient approximation of the density functional theory. We use supercell approach for computational modeling of disordered systems, which gives a description of the properties of the structure baasing on the average over a set of multiple configurations, namely distributions of different species over a given set of atomic positions. The calculations were performed with the CRYSTAL14 program package. The dependence of the band gap and bulk modulus on the content [Formula: see text] are investigated over the whole range [Formula: see text].

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Tunable electronic structure and magnetic moment in C2N nanoribbons with different edge functionalization atoms

Physical Chemistry Chemical Physics ◽

10.1039/c7cp01359k ◽

2017 ◽

Vol 19 (23) ◽

pp. 15021-15029 ◽

Cited By ~ 7

Author(s):

Yusheng Wang ◽

Nahong Song ◽

Min Jia ◽

Dapeng Yang ◽

Chikowore Panashe ◽

...

Keyword(s):

Density Functional Theory ◽

Magnetic Properties ◽

Electronic Structure ◽

Magnetic Moment ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

Electronic And Magnetic Properties

First principles calculations based on density functional theory were carried out to study the electronic and magnetic properties of C2N nanoribbons (C2NNRs).

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Electronic Structure and Hydrogen Desorption in NaAlH4

MRS Proceedings ◽

10.1557/proc-837-n2.5 ◽

2004 ◽

Vol 837 ◽

Cited By ~ 1

Author(s):

S. Li ◽

P. Jena ◽

C. M. Araujo ◽

R. Ahuja

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Metal Hydrides ◽

Hydrogen Desorption ◽

Light Metal ◽

First Principles Calculations ◽

Functional Theory ◽

Design And Synthesis

ABSTRACTFirst principles calculations based on gradient corrected density functional theory are carried out to understand the electronic structure and mechanisms responsible for desorption of hydrogen from Ti doped and vacancy containing sodium-alanate (NaAlH4). The energy necessary to remove a hydrogen atom from Ti doped NaAlH4 is significantly smaller than that from pristine NaAlH4 irrespective of whether Ti substitutes the Na or the Al site. However, the presence of Na and Al vacancies is shown to play an even more important role: The removal of hydrogen associated with both Na and Al vacancies is found to be exothermic. It is suggested that this role of vacancies can be exploited in the design and synthesis of complex light metal hydrides suitable for hydrogen storage.

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Pressure-Induced Tunable Magnetism and Half-Metallic Stability in Co2FeGa Heusler Alloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.477-478.1303 ◽

2013 ◽

Vol 477-478 ◽

pp. 1303-1306

Author(s):

Qin Xiang Gao

Keyword(s):

Fermi Level ◽

First Principles ◽

Density Functional ◽

High Energy ◽

First Principles Calculations ◽

Half Metallicity ◽

Functional Theory ◽

Half Metallic ◽

Heusler Compound ◽

The Density Functional Theory

Using the first-principles calculations within the density functional theory (DFT), we have investigated the structure, magnetism and half-metallic stability of Co2FeGa Heusler compound under pressure from 0 to 50GPa. The results revel that the lattice constant is gradually shrank and total magnetic moment in per unit slightly decreased with increasing pressure, respectively. Moreover, with the increase of the pressure, the Fermi level will move towards high-energy orientation. When the pressure reaches at 30GPa the most stable half-metallicity is observed which the Fermi level is located at the middle of the spin-minority gap.

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