scholarly journals Band gap narrowing in nitrogen-doped La2Ti2O7 predicted by density-functional theory calculations

2015 ◽  
Vol 17 (14) ◽  
pp. 8994-9000 ◽  
Author(s):  
Junying Zhang ◽  
Wenqiang Dang ◽  
Zhimin Ao ◽  
Scott K. Cushing ◽  
Nianqiang Wu

NS co-existing with VO in La2Ti2O7 narrows the band gap and removes the localized energy state, leading to a strong visible light photocatalytic activity and enhancement of the UV performance.

2016 ◽  
Vol 4 (29) ◽  
pp. 11498-11506 ◽  
Author(s):  
Taehun Lee ◽  
Yonghyuk Lee ◽  
Woosun Jang ◽  
Aloysius Soon

Using first-principles density-functional theory calculations, we investigate the advantage of using h-WO3 (and its surfaces) over the larger band gap γ-WO3 phase for the anode in water splitting. We demonstrate that h-WO3 is a good alternative anode material for optimal water splitting efficiencies.


2018 ◽  
Vol 20 (27) ◽  
pp. 18844-18849 ◽  
Author(s):  
Hengxin Tan ◽  
Yuanchang Li ◽  
S. B. Zhang ◽  
Wenhui Duan

Optimal choice of the element-specific pseudopotential improves the band gap.


2016 ◽  
Vol 18 (40) ◽  
pp. 27967-27975 ◽  
Author(s):  
Feiyu Diao ◽  
FengHui Tian ◽  
Wenshuang Liang ◽  
Honglei Feng ◽  
Yiqian Wang

The photocatalytic mechanism of a Cu2O/CuO hybrid system is investigated by density functional theory calculations.


Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 709 ◽  
Author(s):  
Qing-Lu Liu ◽  
Zong-Yan Zhao ◽  
Jian-Hong Yi ◽  
Zi-Yang Zhang

As important functional materials, the electronic structure and physical properties of (GaAs)m(AlAs)n superlattices (SLs) have been extensively studied. However, due to limitations of computational methods and computational resources, it is sometimes difficult to thoroughly understand how and why the modification of their structural parameters affects their electronic structure and physical properties. In this article, a high-throughput study based on density functional theory calculations has been carried out to obtain detailed information and to further provide the underlying intrinsic mechanisms. The band gap variations of (GaAs)m(AlAs)n superlattices have been systematically investigated and summarized. They are very consistent with the available reported experimental measurements. Furthermore, the direct-to-indirect-gap transition of (GaAs)m(AlAs)n superlattices has been predicted and explained. For certain thicknesses of the GaAs well (m), the band gap value of (GaAs)m(AlAs)n SLs exponentially increases (increasing n), while for certain thicknesses of the AlAs barrier (n), the band gap value of (GaAs)m(AlAs)n SLs exponentially decreases (increasing m). In both cases, the band gap values converge to certain values. Furthermore, owing to the energy eigenvalues at different k-points showing different variation trends, (GaAs)m(AlAs)n SLs transform from a Γ-Γ direct band gap to Γ-M indirect band gap when the AlAs barrier is thick enough. The intrinsic reason for these variations is that the contributions and positions of the electronic states of the GaAs well and the AlAs barrier change under altered thickness conditions. Moreover, we have found that the binding energy can be used as a detector to estimate the band gap value in the design of (GaAs)m(AlAs)n devices. Our findings are useful for the design of novel (GaAs)m(AlAs)n superlattices-based optoelectronic devices.


RSC Advances ◽  
2020 ◽  
Vol 10 (27) ◽  
pp. 16179-16186 ◽  
Author(s):  
Shalika R. Bhandari ◽  
D. K. Yadav ◽  
B. P. Belbase ◽  
M. Zeeshan ◽  
B. Sadhukhan ◽  
...  

With the help of density functional theory calculations, we explored the recently synthesized double perovskite material Ca2CrOsO6 and found it to be a ferrimagnetic insulator with a band gap of ∼0.6 eV.


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