نتایج جستجو برای: lsda u

تعداد نتایج: 164987  

Journal: :Physical review letters 2014
Valentin V Karasiev Travis Sjostrom James Dufty S B Trickey

An accurate analytical parametrization for the exchange-correlation free energy of the homogeneous electron gas, including interpolation for partial spin polarization, is derived via thermodynamic analysis of recent restricted path integral Monte Carlo (RPIMC) data. This parametrization constitutes the local spin density approximation (LSDA) for the exchange-correlation functional in density fu...

Journal: :CoRR 2017
Zan Gao Guotai Zhang Feiping Nie Hua Zhang

Dimensionality reduction is a crucial step for pattern recognition and data mining tasks to overcome the curse of dimensionality. Principal component analysis (PCA) is a traditional technique for unsupervised dimensionality reduction, which is often employed to seek a projection to best represent the data in a least-squares sense, but if the original data is nonlinear structure, the performance...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم 1393

اثراتی همچون اثر گرمامغناطیسی، مغناطوتنگش و مغناطومقاومت در خانواده ترکیبات gd5(sixge1-x)4 قابل توجه می باشد که ترکیب gd5si4 نیز بدلیل دارا بودن گذار فاز مغناطیسی نزدیک دمای اتاق قابل توجه می باشد. در این کار، ما ساختار الکترونی و خواص مغناطیسی ترکیب gd5si4 را با روش تابع موج تخت تقویت شده ی خطی با پتانسیل کامل برپایه ی نظریه تابعی چگالی با استفاده از کد محاسباتی wien2k مطالعه کرده ایم. از آنجا...

2008
Klaus Capelle Balazs L. Gyorffy

We use time-dependent spin-density-functional theory to study dynamical magnetic phenomena. First, we recall that the local-spindensity approximation (LSDA) fails to account correctly for magnetic fluctuations in the paramagnetic state of iron and other itinerant ferromagnets. Next, we construct a gradient-dependent density functional that does not suffer from this problem of the LSDA. This fun...

قنبریان, وحید , محمد زاده, محمد رضا ,

  In order to study some theories about nonsuperconductivity of PrBa2Cu3O7, based on the density functional theory and with APW+lo/LAPW method some calculations for PrBa2Cu3O7 (Pr123) and YBa2Cu3O7 (Y123) were performed. The LSDA+U approximation was used for Pr(4f) orbitals and the effect of changing UPr on the band structure, Pr(4f)-DOS, distribution of electrons on the planes and chains, and ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده فیزیک 1388

خواص ساختاری، مغناطیسی و الکترونی انبوهه mnse را به دو روش شبه پتانسیل و پتانسیل کامل با استفاده از دو نرم افزار pwscf و wien2k مورد بررسی قرار دادیم. mnse دارای سه فاز ساختاری nacl ، بلندروی و هگزاگونال از نوع nias است. محاسباتمان را در دوحالت فرومغناطیس و پادفرومغناطیس انجام دادیم. مشاهدات تجربی فاز nacl با نظم پادفرومغناطیسی نوعii ؛یعنی nacl(111) را به عنوان فاز پایدار معرفی کرده است در حالی...

2007
Deepa Kasinathan K Koepernik W E Pickett

The zero temperature Mott transition region in antiferromagnetic, spin S = 52 MnO is probed using the correlated band theory LSDA + U method. The first transition encountered is an insulator–insulator volume collapse within the rocksalt structure that is characterized by an unexpected Hund’s rule violating ‘spin-flip’ moment collapse. This spin-flip to S = 12 takes fullest advantage of the anis...

2015
Gao Weijun Zhang Hong Ke Ming

The curse of dimensionality is a problem of machine learning algorithm which is often encountered on study of high-dimensional data, while LSDA (Locality Sensitive Discriminant Analysis) can solve the problem of curse of dimensionality. However, LSDA can not fully reflect the requirements that the manifold learning for neighborhood, by using the adaptive neighborhood selection method to measure...

2016
N. Christensen O. Gunnarsson O. Jepsen O. Andersen N. E. Christensen

The application of the density-functional theory in the local approximation to magnetic materials is discussed and illustrated by examples. The magnetic properties of the 3d elemental metals as well a s their cohesive properties are described by means of self-consistent local-spin-density (LSD) calculations and by using the LSD-Stoner method. The application of the LSD approximation to narrow-b...

1997
Xiao-Min Tong Shih-I Chu

We present a self-interaction-free density-functional theory ~DFT! for the treatment of both the static properties of the ground states and the photoionization processes of many-electron systems. The method is based on the Krieger-Li-Iafrate ~KLI! treatment of the optimized effective potential ~OEP! theory and the incorporation of an explicit self-interaction correction ~SIC! term. Such an exte...

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