نتایج جستجو برای: تصحیح gga u

تعداد نتایج: 172757  

کاتد در باتری‌های لیتیم-یون مهمترین بخش و تعیین کننده کارآیی و رفتار این وسایل ذخیره انرژی می‌باشد. ماده کاتدی LiFeSO4F با ساختار تاووریت و گروه فضایی C2/c مورد بررسی نظریه تابعی چگالی (DFT) با استفاده از کد Wien2k قرار گرفت. محاسبات با استفاده از روش‌های GGA، GGA+U و PBE-Fock-α (از روش های Hybrid functionals، HF) انجام شدند. محاسبات ساختاری نشان داد این کاتد پس از خروج لیتیم پایداری خود را حفظ...

Abstract: In this work we investigate the electronic, optical, dynamic and thermoelectric properties of ternary copper-based Chalcogenides CuSbX2 (X= S, Se) compounds. Calculations are based on density functional theory and the semi-classical Boltzmann theory. Computations have been carried out by using Quantum-Espresso (PWSCF) package and ab-initio pseudo-potential technique. To estimate the e...

Journal: :Frontiers of Physics in China 2021

The magnetic and electronic properties of strontium titanate with different carbon dopant configurations are explored using first-principles calculations a generalized gradient approximation (GGA) the GGA+U approach. Our results show that structural stability, C-doped SrTiCO3 strongly depend on distance between dopants. In both GGA calculations, doping structure is mostly stable nonmagnetic fea...

2014
Cosima Schuster Matteo Gatti Angel Rubio

We investigate the electronic and magnetic properties of NiS2, which, by varying the chemical composition substituting S by Se atoms or applying pressure, can be driven across various electronic and magnetic phase transitions. By combining several theoretical methods, we highlight the different role played by the chalcogen dimers and the volume compression in determining the phase transitions, ...

2004
Marek Gajdoš Jürgen Hafner

CO adsorption on Cu(111) and Cu(001) surfaces has been studied within ab-initio density functional theory (DFT). The structural, vibrational and thermodynamic properties of the adsorbate-substrate complex have been calculated. Calculations within the generalized gradient approximation (GGA) predict adsorption in the threefold hollow on Cu(111) and in the bridge-site on Cu(001), instead of on-to...

ژورنال: :پژوهش فیزیک ایران 0
علیرضا فقیهی a. r faghihi and s jalali asadabadi faculty of science, university of isfahan, hezar garib avenue, isfahan81744گروه فیزیک، دانشکده علوم، دانشگاه اصفهان، خیابان هزار جریب، اصفهان سعید جلالی اسد آبادی s jalali asadabadi university of isfahan, isfahan 81744.مرکز تحقیقات علوم و تکنولوژی نانو، دانشگاه اصفهان، خیابان هزارجریب، اصفهان

در این مقاله پارامتر هابارد در چارچوب نظریه تابعی چگالی ( dft ) به روش امواج تخت بهبود یافته خطی به علاوه اربیتالهای موضعی با پتانسیل کامل در ترکیب nio و بلور gd به عنوان دستگاههای همبسته قوی که به ترتیب دارای اربیتالهای d 3 و f 4 نیمه پر می باشند با ساختن یک ابر سلول انجام شده است. در ترکیب nio پارامتر هابارد ev 9/5 و در بلور gd این پارامتر برابر با، ev 7/5 محاسبه شده اند. مقادیر محاسبه شده در...

2002
P. M. Oppeneer G. Güntherodt

We report a combined experimental-computational investigation of the electronic structure of CrO2. We have measured the magneto-optical Kerr spectra of CrO2 at 10 K and 300 K. At 10 K the Kerr signal is significantly enhanced over that obtained at 300 K. We compare the measured Kerr spectra to first-principles theoretical spectra, which we computed using three different approximations to the ex...

2009
Roman Kováčik Claude Ederer

We present results of GGA+U calculations for the “d magnet” RbO2, where magnetic properties are due to partially filled oxygen p orbitals. We show that on-site interactions on the oxygen sites lead to a strong tendency towards the formation of an orbitally polarized insulating state, in contrast to the half-metallic behavior predicted for this class of compounds within pure LDA/GGA. The obtaine...

Journal: :Journal of physics. Condensed matter : an Institute of Physics journal 2011
K G Godinho B J Morgan J P Allen D O Scanlon G W Watson

The geometry and electronic structure of copper-based p-type delafossite transparent conducting oxides, CuMO(2) (M = In, Ga, Sc), are studied using the generalized gradient approximation (GGA) corrected for on-site Coulomb interactions (GGA + U). The bonding and valence band compositions of these materials are investigated, and the origins of changes in the valence band features between group 3...

2012
Vincent L. Chevrier Geoffroy Hautier Shyue Ping Ong Robert E. Doe Gerbrand Ceder

First-principles studies of iron oxyfluorides in the FeF2 rutile framework (FeOxF2−x, 0 ≤ x ≤ 1) are performed using density functional theory (DFT) in the general gradient approximation (GGA) with a Hubbard U correction. Studies of O/F orderings reveal FeOF to be particularly stable compared to other FeOxF2−x (x 6= 1) structures, where FeF2–FeOF mixing is not energetically favored. The band ga...

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