Small radius electron and hole polarons in PbX2 (X = F, Cl, Br) crystals: computational study

2021 ◽  
Author(s):  
Yuri Mastrikov ◽  
Nadezhda Chuklina ◽  
Maksim Sokolov ◽  
Anatoli Popov ◽  
Denis Gryaznov ◽  
...  
Keyword(s):  
Dft Calculations ◽  
First Principles ◽  
Computational Study ◽  
Small Radius ◽  
Trapped Electrons

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...

Accelerated Discovery of High-Refractive-Index Polyimides via First-Principles Molecular Modeling, Virtual High-Throughput Screening, and Data Mining

2019 ◽  
Author(s):  
Mohammad Atif Faiz Afzal ◽  
Mojtaba Haghighatlari ◽  
Sai Prasad Ganesh ◽  
Chong Cheng ◽  
Johannes Hachmann
Keyword(s):  
Data Mining ◽  
Refractive Index ◽  
High Throughput ◽  
First Principles ◽  
High Throughput Screening ◽  
Large Scale ◽  
Computational Study ◽  
High Refractive Index ◽  
Structural Features ◽  
Learning Program

<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>

A first-principles study on the electronic and optical properties of a type-II C2N/g-ZnO van der Waals heterostructure

2021 ◽  
Vol 23 (6) ◽  
pp. 3963-3973
Author(s):  
Jianxun Song ◽  
Hua Zheng ◽  
Minxia Liu ◽  
Geng Zhang ◽  
Dongxiong Ling ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dft Calculations ◽  
First Principles ◽  
Van Der Waals ◽  
Band Alignment ◽  
Type Ii ◽  
Electronic And Optical Properties ◽  
Direct Bandgap ◽  
Van Der Waals Heterostructure ◽  
Vdw Heterostructure

The structural, electronic and optical properties of a new vdW heterostructure, C2N/g-ZnO, with an intrinsic type-II band alignment and a direct bandgap of 0.89 eV at the Γ point are extensively studied by DFT calculations.

scholarly journals A Ternary Map of Ni–Mn–Ga Heusler Alloys from Ab Initio Calculations

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 973
Author(s):  
Yulia Sokolovskaya ◽  
Olga Miroshkina ◽  
Danil Baigutlin ◽  
Vladimir Sokolovskiy ◽  
Mikhail Zagrebin ◽  
...  
Keyword(s):  
First Principles ◽  
Predictive Power ◽  
Computational Study ◽  
Heusler Alloys ◽  
Functional Materials ◽  
Ternary Diagram ◽  
Compositional Stability ◽  
Theoretical Predictions ◽  
Simultaneous Stability ◽  
Tetragonal Martensite

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.

Interface coupling and charge doping in graphene on ferroelectric BiAlO3(0001) polar surfaces

2021 ◽  
Vol 23 (5) ◽  
pp. 3407-3416
Author(s):  
Jin Yuan ◽  
Jian-Qing Dai ◽  
Cheng Ke ◽  
Zi-Cheng Wei
Keyword(s):  
Dft Calculations ◽  
Hybrid System ◽  
First Principles ◽  
Doping Effect ◽  
Coupling Mechanism ◽  
Polarization Reversal ◽  
Interface Coupling ◽  
Polar Surfaces ◽  
Charge Doping

The interface coupling mechanism, charge doping effect, and effect of polarization reversal in the graphene/BiAlO3(0001) hybrid system are explored by first-principles DFT calculations.

scholarly journals The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun
Keyword(s):  
Activation Energy ◽  
Dft Calculations ◽  
Energy Barrier ◽  
Computational Study ◽  
Strong Acid ◽  
Activation Energy Barrier ◽  
Pd Catalysts ◽  
Acid Ligand ◽  
Strong Acids

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.

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
Keyword(s):  
First Principles ◽  
Computational Study

Prediction of Beryllium Clusters from First Principles: Be17 as a Promising New Material for Water Splitting

2021 ◽  
Author(s):  
Behnaz Abyaz ◽  
Zabiollah Mahdavifar ◽  
Georg Schreckenbach ◽  
Yang Gao
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Water Splitting ◽  
First Principles ◽  
Density Functional ◽  
Global Minimum ◽  
Functional Theory ◽  
New Material ◽  
Universal Structure

Evolutionary searches using the USPEX method (Universal Structure Predictor: Evolutionary Xtallography) combined with density functional theory (DFT) calculations were performed to obtain the global minimum structures of beryllium (Ben, n=3-25)...

scholarly journals Combining solid-state NMR spectroscopy with first-principles calculations – a guide to NMR crystallography

2016 ◽  
Vol 52 (45) ◽  
pp. 7186-7204 ◽  
Author(s):  
Sharon E. Ashbrook ◽  
David McKay
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
First Principles ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
First Principles Calculations ◽  
Recent Developments ◽  
Future Potential ◽  
Nmr Crystallography

DFT calculations are an important tool in assigning and interpreting NMR spectra of solids: we discuss recent developments and their future potential in the context of NMR crystallography.

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