Synthesis of borophane polymorphs through hydrogenation of borophene

Science ◽  
2021 ◽  
Vol 371 (6534) ◽  
pp. 1143-1148
Author(s):  
Qiucheng Li ◽  
Venkata Surya Chaitanya Kolluru ◽  
Matthew S. Rahn ◽  
Eric Schwenker ◽  
Shaowei Li ◽  
...  
Keyword(s):  
First Principles ◽  
Imaging Spectroscopy ◽  
Atomic Scale ◽  
First Principles Calculations ◽  
Oxidation Rates ◽  
Ambient Exposure ◽  
Correlated Electron ◽  
Chemical Passivation ◽  
Work Functions ◽  
Superlattice Structures

Synthetic two-dimensional polymorphs of boron, or borophene, have attracted attention because of their anisotropic metallicity, correlated-electron phenomena, and diverse superlattice structures. Although borophene heterostructures have been realized, ordered chemical modification of borophene has not yet been reported. Here, we synthesize “borophane” polymorphs by hydrogenating borophene with atomic hydrogen in ultrahigh vacuum. Through atomic-scale imaging, spectroscopy, and first-principles calculations, the most prevalent borophane polymorph is shown to possess a combination of two-center–two-electron boron-hydrogen and three-center–two-electron boron-hydrogen-boron bonds. Borophane polymorphs are metallic with modified local work functions and can be reversibly returned to pristine borophene through thermal desorption of hydrogen. Hydrogenation also provides chemical passivation because borophane reduces oxidation rates by more than two orders of magnitude after ambient exposure.

scholarly journals Preferential proton conduction along a three-dimensional dopant network in yttrium-doped barium zirconate: a first-principles study

2018 ◽  
Vol 6 (45) ◽  
pp. 22721-22730 ◽  
Author(s):  
Kazuaki Toyoura ◽  
Weijie Meng ◽  
Donglin Han ◽  
Tetsuya Uda
Keyword(s):  
First Principles ◽  
Three Dimensional ◽  
Proton Conduction ◽  
Atomic Scale ◽  
Barium Zirconate ◽  
First Principles Calculations ◽  
First Principles Study

The atomic-scale picture of proton conduction in highly doped barium zirconate has theoretically been clarified using first-principles calculations.

Characterisation of the temperature-dependent M1 to R phase transition in W-doped VO2 nanorod aggregates by Rietveld refinement and theoretical modelling

2020 ◽  
Vol 22 (15) ◽  
pp. 7984-7994
Author(s):  
Lei Miao ◽  
Ying Peng ◽  
Dianhui Wang ◽  
Jihui Liang ◽  
Chaohao Hu ◽  
...  
Keyword(s):  
Rietveld Refinement ◽  
First Principles ◽  
Atomic Scale ◽  
Theoretical Modelling ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Macro Scale ◽  
Scale Properties ◽  
W Doping ◽  
Synchrotron Xrd

Synchrotron XRD Rietveld refinement is combined with first-principles calculations to probe the effect of W doping on the IMT mechanism in VO2 nanorods, providing insights into the connection between atomic-scale phenomena and macro-scale properties.

scholarly journals The Nucleation and the Intrinsic Microstructure Evolution of Martensite from 332113β Twin Boundary in β Titanium: First-Principles Calculations

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1202 ◽  
Author(s):  
Chen ◽  
Ma ◽  
Wang
Keyword(s):  
Twin Boundary ◽  
Microstructure Evolution ◽  
First Principles ◽  
Atomic Scale ◽  
Clear Understanding ◽  
Intermediate Structure ◽  
First Principles Calculations ◽  
Ti Alloys ◽  
Α Phase ◽  
Strength And Ductility

A clear understanding on the inter-evolution behaviors between 332113β twinning and stress-induced martensite (SIM) α″ in β-Ti alloys is vital for improving its strength and ductility concurrently. As the preliminary step to better understand these complex behaviors, the nucleation and the intrinsic microstructure evolution of martensite α″ from 332113β twin boundary (TB) were investigated in pure β-Ti at atomic scale using first-principles calculations in this work. We found the α″ precipitation prefers to nucleate and grow at 332113β TB, with the transformation of 332113β TB→130310α” TB. During this process, α″ precipitation firstly nucleates at 332113β TB and, subsequently, it grows inwards toward the grain interiors. This easy transition may stem from the strong crystallographic correspondence between 332113β and 130310α” TBs, and the region close to the 332113β TB presents the characteristics of intermediate structure between β and α″ phases. Kinetics calculations indicate the α″ phase barrierlessly nucleates at 332113β TB rather than in grain interior, where there is higher critical driving energy. Our calculations provide a unique perspective on the “intrinsic” microstructure evolution of martensite α″ from 332113β TB, which may deepen our understanding on the precipitation of martensite α″ and the inter-evolution behaviors between 332113β twinning and martensite α″ in β-Ti alloys at atomic scale.

Transport properties of atomic-size aluminum chains: first principles and nonequilibrium Green's function studies

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91288-91294 ◽  
Author(s):  
F. Sanchez-Ochoa ◽  
Gregorio H. Cocoletzi ◽  
G. Canto ◽  
Noboru Takeuchi
Keyword(s):  
Green’S Function ◽  
Transport Properties ◽  
Green's Function ◽  
Atomic Structure ◽  
First Principles ◽  
Atomic Scale ◽  
First Principles Calculations ◽  
Atomic Size ◽  
Nonequilibrium Green's Function ◽  
Nonequilibrium Green’S Function

First principles calculations are performed to investigate atomic structure and nonequilibrium Green's function for Al atomic scale chains transport properties.

scholarly journals Atomic scale crystal field mapping of polar vortices in oxide superlattices

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sandhya Susarla ◽  
Pablo García-Fernández ◽  
Colin Ophus ◽  
Sujit Das ◽  
Pablo Aguado-Puente ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Crystal Field ◽  
First Principles ◽  
Atomic Scale ◽  
First Principles Calculations ◽  
Edge Structure ◽  
Electron Energy Loss ◽  
Complex Polarization ◽  
Good Agreement

AbstractPolar vortices in oxide superlattices exhibit complex polarization topologies. Using a combination of electron energy loss near-edge structure analysis, crystal field multiplet theory, and first-principles calculations, we probe the electronic structure within such polar vortices in [(PbTiO3)16/(SrTiO3)16] superlattices at the atomic scale. The peaks in Ti $$L$$ L -edge spectra shift systematically depending on the position of the Ti4+ cations within the vortices i.e., the direction and magnitude of the local dipole. First-principles computation of the local projected density of states on the Ti $$3d$$ 3 d orbitals, together with the simulated crystal field multiplet spectra derived from first principles are in good agreement with the experiments.

Tuning the phase transition temperature, electrical and optical properties of VO2 by oxygen nonstoichiometry: insights from first-principles calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73070-73082 ◽  
Author(s):  
Lanli Chen ◽  
Xiaofang Wang ◽  
Dongyun Wan ◽  
Yuanyuan Cui ◽  
Bin Liu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Optical Properties ◽  
Transition Temperature ◽  
Electron Concentration ◽  
First Principles ◽  
Oxygen Nonstoichiometry ◽  
First Principles Calculations ◽  
Electrical And Optical Properties ◽  
Work Functions ◽  
O Vacancy

The O-vacancy in bulk VO2 gives rise to an increase in electron concentration, which induces a decrease in Tc. While, O-vacancy and O-adsorption on VO2(R) (1 1 0) and VO2(M) (0 1 1) surfaces could alter the work functions and in turn regulate Tc.

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