Search query: Electronic structure calculations for rhenium carbonitride: An extended Hückel tight-binding study

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abstract: Effective theoretical models are needed to predict the physical properties of materials. Here we discuss the electronic structure of rhenium carbonitride (ReCN) in terms of tight binding. The extended Huckel tight binding (EHTB) formalism was employed to calculate the band structure, density of states (DOS) and investigate the chemical bonding properties as well as the crystal field splitting (CFS) of d orbitals in the Re atom. Two ReCN structures were studied, characterized by space groups P63mc and P3m1, respectively. The calculated energy bands and DOS depict semiconductor properties for both structures, seeing an indirect band gap of 0.62 eV in P63mc (M K) while a direct band gap of 0.49 eV is seen in P3m1 at (H) Mulliken population and CFS analysis were done to gain insight into the filling of 5d orbitals in ReCN, crystallographical differences between the two crystal structures and their physical implications. The five fold degenerate energy levels in both the P63mc and P3m1 structures are broken by a tetragonal crystal electric field. The P63mc structure undergoes Peierls distortion, resulting in a loss of symmetry. The EHTB method is an effective tool to approximate the physical and chemical properties of novel materials such as ReCN at a low computational cost and in terms of a simple quantum mechanical framework, understood by the broader community. The EHTB model for ReCN will serve as a benchmark and starting point for future studies on the compound within similar contexts.
author_names: Etienne Palos

Jose I Paez

Armando Reyes-Serrato

Donald H Galvan
title: Electronic structure calculations for rhenium carbonitride: an extended Huckel tight binding study
year: 2018

abstract: Abstract Electronic structures of nine cubic perovskite type oxides ABO3's including SrTiO3, SrZrO3, SrHfO3, BaTiO3, BaZrO3, BaHfO3, PbTiO3, PbZrO3 and PbHfO3 were calculated using a band theory based on the self consistent charge extended Huckel tight binding (SCC XHTB) method incorporating the relativistic effects except for the spin orbit interaction in order to examine how the electronic structure changes due to the substitution of the A or B site atom. Moreover, calculations were also made for the tetragonal PbTiO3 to study the electronic structural changes due to the structural change from the cubic phase to the tetragonal one. It is shown that the upper valence band of all the ABO3's considered in the present paper consists of the 2p orbital of oxygen mixed with the d valence electrons of the B atom. The shape remains nearly the same in spite of the A or B site substitution. For the conduction band, it is shown that the bottom of which is made up from the ndt 2g band of the B atom for SrTiO3, SrZrO.
author_names: Michihide Kitamura

Hayden Chen
title: Electronic structure calculations of perovskite type oxides using the self consistent charge extended Huckel tight binding method
year: 1998

abstract: To gain insight into the electronic properties of MoSe2 (molybdenum selenide, also known as drysdallite) electronic structure calculations, total and projected density of states, crystal orbital overlap population and Mulliken population analysis were performed. The calculated energy bands depict a semiconductor behavior with a direct gap (at K) of 0.91 eV and an indirect gap (from G to K) of 3.6 eV, respectively. Total and projected density of states provided information about the contribution from each orbital of each atom to the total density of states. Moreover, the bonding strength between some atoms within the unit cell was obtained. Mulliken population analysis corroborates the electron filling of the Mo dz2 orbitals in agreement with another experimental and theoretical results.
author_names: Donald H Galvan
title: ELECTRONIC STRUCTURE CALCULATIONS FOR MoSe2 USING EXTENDED HUCKEL TIGHT BINDING METHOD
year: 2004

abstract: A transferable tight binding parametrization procedure for extended Huckel approximation is proposed, with the charge self consistent scheme, that could be applied to the quantum molecular dynamics (MD) simulation for long time dynamics of large scale systems. In this procedure, either a target molecule is divided into small molecules or another realistic set of small molecules characterizing chemical bonds in the complicated target molecule is adopted. Then, the parameters for these small molecules are adjusted and compared with reference results of energy levels and wave functions by, for example, density functional theory. Upon application to the large target molecule, these parameters are then readjusted directly in the target molecule. An example is demonstrated with MD simulation applied to the ionic liquid molecule N methyl N propylpiperidinium bis trifluoromethanesulfonyl imide (PP13 TFSI) The origin and stability of HOMO LUMO gap are discussed.
author_names: Shinya Nishino

Takeo Fujiwara
title: Parametrization scheme with accuracy and transferability for tight binding electronic structure calculations with extended Huckel approximation and molecular dynamics simulations
venue: Journal of Molecular Modeling
year: 2013

abstract: Abstract The spin polarized self consistent charge extended Huckel tight binding (SP SCC XHTB) method has been developed by authors to study the electronic structures of rutile type transition metal dioxides, MO2, with both the nonmagnetic and magnetic phases. This method has been used to successfully predict the electronic structures of nonmagnetic (n) MO2's with M =Ti, V, Nb, Ta, Cr and ferromagnetic (f) CrO2, but is inadequate to predict the value of the energy gap of a semiconductive n MnO2. The SP SCC XHTB band structure calculation, which includes all the relativistic effects in a first principal manner, has only one empirical parameter on the evaluation of the matrix elements of the non relativistic Hamiltonian H0. In this paper, the SP SCC XHTB method is improved so as to evaluate the matrix elements of the H0 in a more appropriate manner. The band structure calculations are carried out for the n MO2's with M =Ti, V, Nb, Ta, Cr and Mn, the f CrO2 and the af MnO2. With the improvement it is shown that the SP SCC IXHTB band structure calculations give reasonable results for the electronic structures of all the MO2's considered in the present paper.
author_names: Michihide Kitamura

Kanryu Inoue

Haydn H D Chen
title: Improvement of the spin polarized self consistent charge extended Huckel tight binding method
year: 2000

abstract: The extended Huckel (eH) tight binding method has historically been prized for its computational ease and intuitive chemical clarity. However, its lack of quantitative predictiveness has prevented the eH method from being used as a tool for rapidly screening materials for desired electronic properties. In this work, we demonstrate that when eH input parameters are calibrated using density functional theory (DFT) calculations of carefully chosen sets of simple crystals, the eH parameters retain most of their quantitative accuracy when transferred to more complex, structurally related phases. Using solar energy relevant semiconductors and insulators in the Sr Ti O family as a case study, we show that calibrated eH parameters can match the features of DFT band structures within about two tenths of an eV, at a tiny fraction of the computational cost of DFT.
author_names: Linda Grabill

Robert F Berger
title: Calibrating the Extended Huckel Method to Quantitatively Screen the Electronic Properties of Materials
venue: Scientific Reports
year: 2018

abstract: In this work, we present a theoretical study of the electronic properties of group IV element nanosheets, namely graphene, silicene, germanene and the corresponding hydrogenated structures for the two latter, silicane and germanane. We compare the results of two different calculation methods, Density Functional Theory (DFT) and Extended Huckel Theory (EHT) for both pristine sheets and sheets of silicene and germanene with a single atom vacancy. We show that EHT offers a remarkably reliable description of the electronic structure of these materials for all cases, thus offering an affordable way for studying large systems for which DFT calculations would be expensive and lengthy.
author_names: Adriano S Martins

Marcos Verissimo-Alves
title: Group IV nanosheets with vacancies: a tight binding extended Huckel study.
venue: Journal of physics. Condensed matter an Institute of Physics journal
year: 2014

abstract: In this work, we performed tight binding calculations of the electronic structure of III V semiconductors compounds and their alloys based on the Extended Huckel Theory (EHT) In particular, this paper is focused on the dependency between band gap and the applied pressure and also the alloy composition.
author_names: Ingrid A Ribeiro

Fabio J Ribeiro

Adriano S Martins
title: An extended Huckel study of the electronic properties of III V compounds and their alloys
year: 2014

abstract: Abstract Band theory based on the spin polarized self consistent charge extended Huckel tight binding (SP SCC XHTB) method, which includes all the relativistic effects and the spin polarized self consistent field (SP SCF) atomic structure calculation based on the Hartree Fock Slater method, has been applied to the electronic structure calculations of tetragonal rutile type MO2s, such as nonmagnetic (n) TiO2, VO2, NbO2, TaO2, CrO2, MnO2, ferromagnetic (f) CrO2 and antiferromagnetic (af) MnO2. It is shown that the calculations are consistent with the experimental observations for all systems except the case of MnO2. It is demonstrated that the semiconductive nature of MnO2 can be explained by adding an assumption that three electrons in the Mn t2g orbital are localized in the crystal into the SP SCC XHTB band structure calculation.
author_names: Michihide Kitamura

Kanryu Inoue

Haydn H D Chen
title: Electronic structures of transition metal dioxides studied by the spin polarized self consistent charge extended Huckel tight binding method
year: 1998

abstract: We perform extended calculations of composed carbon structures where carbon acquires its sp or sp hybrid character. Based on an existing implementation of a tight binding (TB) model for carbon, we implement the calculation of the forces using the Hellmann Feynman theorem. The forces make it possible to use fast minimization algorithms to relax carbon nanostructures composed of up to several hundred atoms. We focus our investigation on carbynes (sp character) inserted in a nanohole inside a graphene sheet (sp character) and on carbon nanotubes mainly (sp character) After relaxation we compute the electronic structure, in particular we evaluated the band gaps for semiconducting nanotubes. The results are compared to DFT calculation and experimental observations. Finally, taking advantage of the forces, we perform molecular dynamics simulations of carbynes in graphene at high temperature, to investigate the stability of such a system. Advisor: Dr. Nicola Manini Co Advisor: Prof. Giovanni Onida
author_names: Nicola Manini

Giovanni Onida

Nicola Ferri
title: Universita degli Studi di Milano Facolta di Scienze Matematiche Fisiche e Naturali Laurea Triennale in Fisica Structural and electronic properties of carbon nanostructures a tight binding study
year: 2010