Temperature-Driven Phase Transition and Transition Dipole Moment of Two-Dimensional (BA)2CsPb2Br7 Perovskite

2021 ◽  
Author(s):  
Jia Lin ◽  
Yajing Wang ◽  
Qilin Song ◽  
Wenjing Hu ◽  
Dan Wang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Dipole Moment ◽  
First Principles ◽  
Transition Dipole Moment ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Transition Dipole ◽  
Temperature Range ◽  
Halide Perovskite

The structures of hybrid two-dimensional (2D) Ruddlesden-Popper (RP) phase layered halide perovskite (BA)2CsPb2Br7 in the temperature range of 100 to 450 K were constructed and systematically investigated by first-principles calculations....

scholarly journals The Features of Phase Stability of GaN and AlN Films at Nanolevel

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Ilya V. Chepkasov ◽  
Sergey V. Erohin ◽  
Pavel B. Sorokin
Keyword(s):  
Phase Transition ◽  
Systematic Study ◽  
Phase Stability ◽  
First Principles ◽  
Film Structure ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Detailed Understanding ◽  
Thickness Increase ◽  
Optical And Electronic Properties

Recently, two-dimensional gallium and aluminum nitrides have triggered a vast interest in their tunable optical and electronic properties. Continuation of this research requires a detailed understanding of their atomic structure. Here, by using first-principles calculations we reported a systematic study of phase stability of 2D-GaN and 2D-AlN. We showed that the films undergo a phase transition from a graphene-like to a wurtzite structure with a thickness increase, whereas the early reported body-centered-tetragonal phase requires specific conditions for stabilization. Additionally, we studied how the functionalization of the surface can modify the film structure as exemplified by hydrogenation.

scholarly journals Dipole-induced Ohmic contacts between monolayer Janus MoSSe and bulk metals

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Ning Zhao ◽  
Udo Schwingenschlögl
Keyword(s):  
First Principles ◽  
Ohmic Contacts ◽  
Electrode Materials ◽  
Electronic Device ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Fermi Level Pinning ◽  
Common Electrode ◽  
Two Sides ◽  
Metallic Electrodes

AbstractUtilizing a two-dimensional material in an electronic device as channel layer inevitably involves the formation of contacts with metallic electrodes. As these contacts can dramatically affect the behavior of the device, we study the electronic properties of monolayer Janus MoSSe in contact with different metallic electrodes by first-principles calculations, focusing on the differences in the characteristics of contacts with the two sides of MoSSe. In particular, we demonstrate that the Fermi level pinning is different for the two sides of MoSSe, with the magnitude resembling that of MoS2 or MoSe2, while both sides can form Ohmic contacts with common electrode materials without any further adaptation, which is an outstanding advantage over MoS2 and MoSe2.

scholarly journals Two-dimensional Weyl points and nodal lines in pentagonal materials and their optical response

Nanoscale ◽  
2021 ◽  
Author(s):  
Sergio Bravo ◽  
M. Pacheco ◽  
V. Nuñez ◽  
J. D. Correa ◽  
Leonor Chico
Keyword(s):  
First Principles ◽  
Optical Response ◽  
Symmetry Analysis ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Nodal Lines

A symmetry analysis combined with first-principles calculations of two-dimensional pentagonal materials (PdSeTe, PdSeS, InP5 and GeBi2) based on the Cairo tiling reveal nontrivial spin textures, nodal lines and Weyl points.

Ferromagnetic Dirac Half-Metallicity in Transition Metal Embedded Honeycomb Borophene

2021 ◽  
Author(s):  
Yanxia Wang ◽  
Xue Jiang ◽  
Yi Wang ◽  
Jijun Zhao
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Valence Electron ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Next Generation ◽  
Half Metallicity ◽  
Counting Rule ◽  
Spintronic Devices ◽  
Electron Counting

Exploring two-dimensional (2D) ferromagnetic materials with intrinsic Dirac half-metallicity is crucial for the development of next-generation spintronic devices. Based on first-principles calculations, here we propose a simple valence electron-counting rule...

SIn2Te/TeIn2Se: a type-II heterojunction as water-splitting photocatalyst with high solar energy harvesting

2021 ◽  
Author(s):  
Peishen Shang ◽  
Chunxiao Zhang ◽  
Mengshi Zhou ◽  
Chaoyu He ◽  
Tao Ouyang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Solar Energy ◽  
Water Splitting ◽  
First Principles ◽  
Type Ii ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Solar Energy Harvesting ◽  
Renewable Hydrogen

Searching for photocatalysts is crucial for the production of renewable hydrogen from water. Two-dimensional (2D) vdW heterojunctions show great potential. Using first- principles calculations within the HSE06 functional, we propose...

Theoretical studies on the one- and two-photon absorption of tetrabenzoporphyrins and phthalocyanines

2004 ◽  
Vol 82 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Xin Zhou ◽  
Ai-Min Ren ◽  
Ji-Kang Feng ◽  
Xiao-Juan Liu
Keyword(s):  
Dipole Moment ◽  
Cross Sections ◽  
Density Functional ◽  
Transition Dipole Moment ◽  
Photon Absorption ◽  
Transition Dipole ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Order Of Magnitude ◽  
The One

The one-photon absorption (OPA) properties of tetrabenzoporphyrins (TBPs) and phthalocyanines (Pcs) were studied using the semiempirical ZINDO method and time-dependent density functional theory (TDDFT), respectively. The compared results confirmed that the semiempirical ZINDO method was reasonably reliable when calculating the OPA of tetrabenzoporphyrins and phthalocyanines. On the basis of the OPA properties obtained from the ZINDO method, two-photon absorption (TPA) properties of two series of molecules were investigated, using ZINDO and sum-over-states (SOS) methods. The results showed that the TPA cross-sections of all molecules were in the range of 220.6 × 10–50 – 345.9 × 10–50 cm4·s·photon–1, which were in the same order of magnitude as the values reported in the literature. The relatively larger δ(ω) value for Pcs with respect to that for corresponding TBPs originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment between S0 and S1 and the transition dipole moment between S1 and S5.Key words: two-photon absorption, ZINDO, sum-over-states, tetrabenzoporphyrin, phthalocyanines.

Designing two Dimensional Dodecagonal Boron Nitride

CrystEngComm ◽  
2022 ◽  
Author(s):  
Hajime Suzuki ◽  
Itsuki Miyazato ◽  
Tanveer Hussain ◽  
Fatih Ersan ◽  
Satoshi Maeda ◽  
...  
Keyword(s):  
Boron Nitride ◽  
First Principles ◽  
Two Dimensional ◽  
First Principles Calculations

Two-dimensional dodecagonal boron nitride is designed via first principles calculations. Calculations unveil that the proposed two-dimensional dodecagonal boron nitride is energetically stable and less dense than what is observed with...

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