First-principles study of bandgap tuning in Ge1−xPbxSe

2018 ◽  
Vol 32 (07) ◽  
pp. 1850076
Author(s):  
Himanshu Lohani

Narrow bandgap and its tuning are important aspects of materials for their technological applications. In this context group IV–VI semiconductors are one of the interesting candidates. In this paper, we explore the possibility of bandgap tuning in one of the family member of this family GeSe by using isoelectronic Pb doping. Our study is first-principles based electronic structure calculations of Ge[Formula: see text]Pb[Formula: see text]Se. This study reveals that the Ge-p and Se-p states are strongly hybridized in GeSe and shows a gap in the DOS at Ef in GeSe. This gap reduces systematically with simultaneous enhancement of the states in the near Ef region as a function of Pb doping. This leads tuning of the indirect bandgap in GeSe via Pb doping. The results of the indirect bandgap decrement are consistent with the experimental findings. We propose a mechanism where the electrostatic effect of dopant Pb cation could be responsible for these changes in the electronic structure of GeSe.

1993 ◽  
Vol 319 ◽  
Author(s):  
N. Kioussis ◽  
H. Watanabe ◽  
R.G. Hemker ◽  
W. Gourdin ◽  
A. Gonis ◽  
...  

AbstractUsing first-principles electronic structure calculations based on the Linear-Muffin-Tin Orbital (LMTO) method, we have investigated the effects of interstitial boron and hydrogen on the electronic structure of the L12 ordered intermetallic Ni3A1. When it occupies an octahedral interstitial site entirely coordinated by six Ni atoms, we find that boron enhances the charge distribution found in the strongly-bound “pure” Ni3AI crystal: Charge is depleted at Ni and Al sites and enhanced in interstitial region. Substitution of Al atoms for two of the Ni atoms coordinating the boron, however, reduces the interstitial charge density between certain atomic planes. In contrast to boron, hydrogen appears to deplete the interstitial charge, even when fully coordinated by Ni atoms. We suggest that these results are broadly consistent with the notion of boron as a cohesion enhancer and hydrogen as an embrittler.


2019 ◽  
Vol 48 (5) ◽  
pp. 3059-3068 ◽  
Author(s):  
O. Y. Khyzhun ◽  
V. L. Bekenev ◽  
N. M. Denysyuk ◽  
L. I. Isaenko ◽  
A. P. Yelisseyev ◽  
...  

Author(s):  
Stewart J. Clark ◽  
Matthew D. Segall ◽  
Chris J. Pickard ◽  
Phil J. Hasnip ◽  
Matt I. J. Probert ◽  
...  

AbstractThe CASTEP code for first principles electronic structure calculations will be described. A brief, non-technical overview will be given and some of the features and capabilities highlighted. Some features which are unique to CASTEP will be described and near-future development plans outlined.


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