Estimation of spin contamination errors in DFT/plane-wave calculations of solid materials using approximate spin projection scheme

2021 ◽  
Vol 765 ◽  
pp. 138291
Author(s):  
Kohei Tada ◽  
Shusuke Yamanaka ◽  
Takashi Kawakami ◽  
Yasutaka Kitagawa ◽  
Mitsutaka Okumura ◽  
...  
Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 505 ◽  
Author(s):  
Kohei Tada ◽  
Tomohiro Maruyama ◽  
Hiroaki Koga ◽  
Mitsutaka Okumura ◽  
Shingo Tanaka

The aggregation of Au atoms onto a Au dimer (Au2) on a MgO (001) surface was calculated by restricted (spin-un-polarized) and unrestricted (spin-polarized) density functional theory calculations with a plane-wave basis and the approximate spin projection (AP) method. The unrestricted calculations included spin contamination errors of 0.0–0.1 eV, and the errors were removed using the AP method. The potential energy curves for the aggregation reaction estimated by the restricted and unrestricted calculations were different owing to the estimation of the open-shell structure by the unrestricted calculations. These results show the importance of the open-shell structure and correction of the spin contamination error for the calculation of small-cluster-aggregations and molecule dimerization on surfaces.


2021 ◽  
Author(s):  
Kohei Tada ◽  
Masahiro Mori ◽  
Shingo Tanaka

2019 ◽  
Vol 12 (11) ◽  
pp. 115506 ◽  
Author(s):  
Kohei Tada ◽  
Shingo Tanaka ◽  
Takashi Kawakami ◽  
Yasutaka Kitagawa ◽  
Mitsutaka Okumura ◽  
...  

Author(s):  
J. M. Pankratz

It is often desirable in transmission electron microscopy to know the vertical spacing of points of interest within a specimen. However, in order to measure a stereo effect, one must have two pictures of the same area taken from different angles, and one must have also a formula for converting measured differences between corresponding points (parallax) into a height differential.Assume (a) that the impinging beam of electrons can be considered as a plane wave and (b) that the magnification is the same at the top and bottom of the specimen. The first assumption is good when the illuminating system is overfocused. The second assumption (the so-called “perspective error”) is good when the focal length is large (3 x 107Å) in relation to foil thickness (∼103 Å).


1997 ◽  
Vol 92 (3) ◽  
pp. 477-487 ◽  
Author(s):  
GERALD LIPPERT ◽  
JuRG HUTTER ◽  
MICHELE PARRINELLO

2002 ◽  
Vol 727 ◽  
Author(s):  
A. M. Mazzone

AbstractFull Potential Linearized Augmented Plane Wave calculations have been performed for epitaxial multilayers formed by the noble metals Ag and Cu with a thickness n up to 10 layers. The multilayers have a fcc lattice and are pure or compositionally modulated with a structure of the type Agn Cun or (AgCu)n. For n in the range 2,3 the density of states, evaluated at paramagnetic level, exhibits a sharp reduction of the bandwidth which is consistent with the reduced coordination of these structures. For n ≤ 5 the density of states in the central layers converges to the bulk value while the outer layers retain the narrow bandwidth found at n=2. Due to the absence of charge intermixing and hybridization, these features are shared by multilayers of all composition.


1998 ◽  
Author(s):  
Lawrence Grimes ◽  
John Roberts ◽  
Ralph Rudder

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