Factors Favoring Ferroelectricity in Hafnia: A First-Principles Computational Study

2017 ◽  
Vol 121 (8) ◽  
pp. 4139-4145 ◽  
Author(s):  
Rohit Batra ◽  
Tran Doan Huan ◽  
Jacob L. Jones ◽  
George Rossetti ◽  
Rampi Ramprasad
2019 ◽  
Author(s):  
Mohammad Atif Faiz Afzal ◽  
Mojtaba Haghighatlari ◽  
Sai Prasad Ganesh ◽  
Chong Cheng ◽  
Johannes Hachmann

<div>We present a high-throughput computational study to identify novel polyimides (PIs) with exceptional refractive index (RI) values for use as optic or optoelectronic materials. Our study utilizes an RI prediction protocol based on a combination of first-principles and data modeling developed in previous work, which we employ on a large-scale PI candidate library generated with the ChemLG code. We deploy the virtual screening software ChemHTPS to automate the assessment of this extensive pool of PI structures in order to determine the performance potential of each candidate. This rapid and efficient approach yields a number of highly promising leads compounds. Using the data mining and machine learning program package ChemML, we analyze the top candidates with respect to prevalent structural features and feature combinations that distinguish them from less promising ones. In particular, we explore the utility of various strategies that introduce highly polarizable moieties into the PI backbone to increase its RI yield. The derived insights provide a foundation for rational and targeted design that goes beyond traditional trial-and-error searches.</div>


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 973
Author(s):  
Yulia Sokolovskaya ◽  
Olga Miroshkina ◽  
Danil Baigutlin ◽  
Vladimir Sokolovskiy ◽  
Mikhail Zagrebin ◽  
...  

In the search for new magnetic functional materials, non-stoichiometric compounds remain a relatively unexplored territory. While experimentalists create new compositions looking for improved functional properties, their work is not guided by systematic theoretical predictions. Being designed for perfect periodic crystals, the majority of first-principles approaches struggle with the concept of a non-stoichiometric system. In this work, we attempt a systematic computational study of magnetic and structural properties of Ni–Mn–Ga, mapped onto ternary composition diagrams. Compositional stability was examined using the convex hull analysis. We show that the cubic austenite has its stability region close to the stoichiometric Ni2MnGa, in agreement with experimental data, while the tetragonal martensite spreads its stability over a wider range of Mn and Ni contents. The unstable compositions in both austenite and martensite states are located in the Ga-rich corner of the ternary diagram. We note that simultaneous stability of the austenite and martensite should be considered for potentially stable compounds suitable for synthesis. The majority of compounds are predicted to be ferrimagnetically ordered in both austenitic and martensitic states. The methodology used in this work is computationally tractable, yet it delivers some predictive power. For experimentalists who plan to synthesize stable Ni–Mn–Ga compounds with ferromagnetic order, we narrow the target compositional range substantially.


2019 ◽  
Vol 21 (45) ◽  
pp. 25397-25405
Author(s):  
Shukai Yao ◽  
Pilsun Yoo ◽  
Peilin Liao

First principles density functional theory calculations were performed to identify transition metal perovskites CaFeO3, SrFeO3, BaFeO3 and SmMnO3 as promising candidates with large band gap opening upon hydrogen doping.


2010 ◽  
Vol 82 (17) ◽  
Author(s):  
Vitaly Alexandrov ◽  
Niels Grønbech-Jensen ◽  
Alexandra Navrotsky ◽  
Mark Asta

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4739
Author(s):  
Shaoying Guo ◽  
Hao Lin ◽  
Jiapeng Hu ◽  
Zhongliang Su ◽  
Yinggan Zhang

Seeking candidate photocatalysts for photocatalytic water splitting, via visible light, is of great interest and importance. In this study, we have comprehensively explored the crystal structures, electronic properties, and optical absorbance of two-dimensional (2D) Sc2CT2 (T = F, Cl, Br) MXenes and their corresponding photocatalytic water splitting, under the visible-light region, by first-principles calculations. Herein, we have proposed that 2D Sc2CT2 MXenes can be fabricated from their layered bulk compounds, alternatively to the traditional chemical etching method. Creatively, we proposed Sc2CT2 (T = F, Br) as new materials; the band edge alignments of Sc2CF2 can be tuned to meet the water redox potentials at pH = 8.0. It is highlighted that Sc2CF2 shows outstanding optical spectra harvested under visible-light wavelength regions, and efficient separation of photo-induced electrons and holes in different zones. These present results provide eloquent evidence and open a new door on the photocatalysis applications of such novel semiconducting MXenes.


Author(s):  
Yuri Mastrikov ◽  
Nadezhda Chuklina ◽  
Maksim Sokolov ◽  
Anatoli Popov ◽  
Denis Gryaznov ◽  
...  

The first principles hybrid DFT calculations were performed for small radius polarons - self-trapped electrons (STEL) and holes (STH) in PbX2 (X = F, Cl, Br) crystals, widely used as...


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