Electronic Structures of Ga- and Zn- Substituted Yba2Cu3O7 Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
Yong-Nian Xu ◽  
W.Y. Ching ◽  
K.W. Wong

AbstractThe band structures of YBa2Cu307 superconductors in which one of the Cu atoms was replaced by Ga or Zn have been studied by the first‐principles orthogonalized LCAO method. Substitutions involving Cu on the chain site and Cu on the plane site were investigated. Results show significant modifications in the electronic structure due to the dopant‐specific and site‐specific substitutions. These results are discussed in light of some recent experimental observations.

RSC Advances ◽  
2020 ◽  
Vol 10 (30) ◽  
pp. 17829-17835
Author(s):  
Xiaotian Wang ◽  
Mengxin Wu ◽  
Tie Yang ◽  
Rabah Khenata

By first-principles calculations, for Heusler alloys Pd2CrZ (Z = Al, Ga, In, Tl, Si, Sn, P, As, Sb, Bi, Se, Te, Zn), the effect of Zn doping on their phase transition and electronic structure has been studied in this work.


RSC Advances ◽  
2020 ◽  
Vol 10 (60) ◽  
pp. 36295-36302
Author(s):  
Zhinan Cao ◽  
Na Jin ◽  
Jinwen Ye ◽  
Xu Du ◽  
Ying Liu

First-principles calculations are carried out by DFT within the CASTEP plane wave code to investigate the mechanical properties and electronic structure of N and Al doped TiC.


2007 ◽  
Vol 345-346 ◽  
pp. 959-962
Author(s):  
Yusuke Kinoshita ◽  
Yoshitaka Umeno ◽  
Takayuki Kitamura

Using the first-principles calculation, the elastic constant C44 of Ag/Al multilayers with different modulation periods from 0.43 nm to 2.27 nm has been evaluated in order to examine the effect of atomic and electronic structures on it. With increasing modulation period, C44 decreases and becomes close to that obtained by the conventional mixing rule, however, the difference of 8 % still remains at the modulation period of 2.27 nm. As C44 correlates with the average interplanar spacing, the decrease of C44 can be explained by the decrease of the charge density in the stacking direction due to the increase of the average interplanar spacing. The difference in the electronic structure is included in the effect of atomic structure.


2021 ◽  
Vol 2083 (2) ◽  
pp. 022002
Author(s):  
Haifeng Zhang ◽  
Caiping Cheng ◽  
Bin Wang

Abstract First principles method is used to study the adsorption behavior, formation energy and electronic structure of IIIA (B, Al, Ga, In) atoms adsorbed on Top, T4 and H3 sites of ZnO (0001) surface. The date shows that the formation energy of B, Al, Ga and In atoms adsorbed on Top site is highest, then followed by T4 site, and H3 is a more stable adsorption site. With the periodic increase of B, Al, Ga and In atoms, the formation energy of corresponding models decreases gradually, and the binding ability with O atoms also decreases gradually. The electronic structure of ZnO (0001) surface is sensitive to the adsorption sites. When these atoms are adsorbed on Top sites, the electronic structures of B-Top, Al-Top, Ga-Top and In-Top models have a little change compared with ZnO (0001) surface. However, when these atoms are adsorbed on T4 and H3 sites, the impurity states appear on the VBM, which narrowing the band gap of the corresponding models.


1987 ◽  
Vol 99 ◽  
Author(s):  
W. Y. Ching ◽  
Yongnian Xu ◽  
K. W. Wong

ABSTRACTThe electronic structures of fluorine-substituted YBa2Cu3O7. crystals are studied by means of first-principles calculations. The most likely site of substitution is 0(1) and the most unlikely site is 0(4).


2017 ◽  
Vol 31 (29) ◽  
pp. 1750265 ◽  
Author(s):  
Guangtao Wang ◽  
Dongyang Wang ◽  
Xianbiao Shi ◽  
Yufeng Peng

We studied the crystal and electronic structures of LaOBiSSe and LaOBiSeS using first-principles calculations and confirmed that the LaOBiSSe (S atoms on the top of BiCh2 layer and Se atoms in the inner of it) is the stable structure. Then we calculate the thermoelectric properties of LaOBiSSe using the standard Boltzmann transport theory. The in-plane thermoelectric performance are better than that along the c-axis in this n-type material. The in-plane power factor [Formula: see text] of n-type LaOBiSSe is as high as 12 [Formula: see text]W/cmK2 at 900 K with figure of merit ZT = 0.53 and [Formula: see text]. The ZT maximum appears around [Formula: see text] in a wide temperature region. The results indicate that LaOBiSSe is a 2D material with good thermal performance in n-type doping.


2015 ◽  
Vol 29 (24) ◽  
pp. 1550136
Author(s):  
Shuying Zhong ◽  
Xueling Lei ◽  
Lang Zhou

Atomic and electronic structures of monovacancy (V1), divacancy (V2) and ring hexavacancy (V6) in crystalline silicon are studied using first-principles calculations in periodic supercells. Our results show that the V6 defect is the most stable among V1, V2 and V6 defects, and the V2-RB structure is a little more stable than the V2-LP structure due to lower vacancy formation energy. Furthermore, it is found that both V1 and V2 undergo the Jahn–Teller (JT) distortion while V6 does not. As a result, V1 and V2 have deep levels in the gap which mainly come from the neighboring atoms to vacancy. V6 has tailing bands in the gap, and so has a more stable electronic structure than V1 and V2. In addition, the JT distortion also reflects in the band decomposed charge density and the difference charge density.


2015 ◽  
Vol 08 (06) ◽  
pp. 1550064 ◽  
Author(s):  
Lin Feng ◽  
Wenxing Zhang ◽  
Enke Liu ◽  
Wenhong Wang ◽  
Guangheng Wu

The phase stability, electronic structure and magnetism of Pt 2-x Mn 1+x In (x = 0, 0.25, 0.5, 0.75, 1) alloys are studied by first-principles calculations. The possible magnetic martensitic transformation in this series has been investigated. For all the five compounds, the energy minimums occur around c/a = 1.30, and the energy differences between the austenitic and martensitic phases are large enough to overcome the resistance of phase transformation. By comparing the electronic structures of austenitic and martensitic phases, we can find that the phase stability is enhanced by the martensitic transformation. The magnetic structures of the austenitic and martensitic phases are also discussed.


2021 ◽  
Author(s):  
Yumeng Fo ◽  
Yanxia Ma ◽  
Hao Dong ◽  
Xin Zhou

Codoping with cation and anion is found to be an effective approach to tailor the electronic structures of semiconductor-based photocatalysts. In this work, a systematic hybrid density functional study has...


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