Pressure-Induced Changes in the Structure and Band Gap of CsGeX3(X = Cl, Br) Studied by Electronic Band Structure Calculations

1998 ◽  
Vol 37 (3) ◽  
pp. 407-410 ◽  
Author(s):  
D.-K. Seo ◽  
N. Gupta ◽  
M.-H. Whangbo ◽  
H. Hillebrecht ◽  
G. Thiele
Keyword(s):  
Band Structure ◽  
Band Gap ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Band Structure Calculations ◽  
Induced Changes ◽  
Structure Calculations

NaGe6As6: Insertion of sodium into the layered semiconductor germanium arsenide GeAs

2016 ◽  
Vol 71 (5) ◽  
pp. 375-380 ◽  
Author(s):  
Mansura Khatun ◽  
Arthur Mar
Keyword(s):  
Band Structure ◽  
Fermi Level ◽  
Band Gap ◽  
Electronic Band Structure ◽  
Structure Type ◽  
Monoclinic Structure ◽  
Layered Semiconductor ◽  
Electronic Band ◽  
Band Structure Calculations ◽  
Structure Calculations

AbstractNaGe6As6 is a ternary arsenide prepared by reaction of the elements at 650 °C. It crystallizes in a new monoclinic structure type [space group C2/m, Z = 2, a = 22.063(2), b = 3.8032(4), c = 7.2020(8) Å, β = 92.7437(15)°] that can be considered to be derived by inserting guest Na atoms between [Ge6As6] layers identical to those found in the layered binary arsenide GeAs. An unusual feature in both structures is the presence of ethane-like Ge2As6 units in staggered conformation, with Ge–Ge dumbbells oriented either parallel or perpendicular to the layers. Electronic band structure calculations have shown that the electron excess in NaGe6As6 is accommodated by raising the Fermi level across a 0.6 eV band gap in semiconducting GeAs so that it cuts the bottom of the conduction band, resulting in an n-doped semiconductor.

Efficient Discovery of Optimal N-Layered TMDC Hetero-Structures

MRS Advances ◽  
2018 ◽  
Vol 3 (6-7) ◽  
pp. 397-402 ◽  
Author(s):  
Lindsay Bassman ◽  
Pankaj Rajak ◽  
Rajiv K. Kalia ◽  
Aiichiro Nakano ◽  
Fei Sha ◽  
...  
Keyword(s):  
Band Structure ◽  
Physical Properties ◽  
Band Gap ◽  
Electronic Band Structure ◽  
Transport Coefficients ◽  
Optimization Technique ◽  
Bayesian Optimization ◽  
Material Structure ◽  
Electronic Band ◽  
Structure Calculations

ABSTRACTVertical hetero-structures made from stacked monolayers of transition metal dichalcogenides (TMDC) are promising candidates for next-generation optoelectronic and thermoelectric devices. Identification of optimal layered materials for these applications requires the calculation of several physical properties, including electronic band structure and thermal transport coefficients. However, exhaustive screening of the material structure space using ab initio calculations is currently outside the bounds of existing computational resources. Furthermore, the functional form of how the physical properties relate to the structure is unknown, making gradient-based optimization unsuitable. Here, we present a model based on the Bayesian optimization technique to optimize layered TMDC hetero-structures, performing a minimal number of structure calculations. We use the electronic band gap and thermoelectric figure of merit as representative physical properties for optimization. The electronic band structure calculations were performed within the Materials Project framework, while thermoelectric properties were computed with BoltzTraP. With high probability, the Bayesian optimization process is able to discover the optimal hetero-structure after evaluation of only ∼20% of all possible 3-layered structures. In addition, we have used a Gaussian regression model to predict not only the band gap but also the valence band maximum and conduction band minimum energies as a function of the momentum.

Ab initio electronic band structure calculations of half-metallic c alcium pnictides

2007 ◽  
Vol 244 (12) ◽  
pp. 4643-4650 ◽  
Author(s):  
G. Jaiganesh ◽  
R. D. Eithiraj ◽  
G. Kalpana ◽  
M. Rajagopalan
Keyword(s):  
Band Structure ◽  
Ab Initio ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Half Metallic ◽  
Band Structure Calculations ◽  
Structure Calculations
Sign in / Sign up

Export Citation Format

Share Document