First-Principles Calculations of AlN Nanowires and Nanotubes:  Atomic Structures, Energetics, and Surface States

2006 ◽  
Vol 110 (17) ◽  
pp. 8764-8768 ◽  
Author(s):  
Mingwen Zhao ◽  
Yueyuan Xia ◽  
Xiangdong Liu ◽  
Zhenyu Tan ◽  
Boda Huang ◽  
...  
Keyword(s):  
First Principles ◽  
Surface States ◽  
First Principles Calculations ◽  
Atomic Structures

Magnetism and Half-Metallicity in (100) Surface of Inverse Heusler Mn2CoSb

2014 ◽  
Vol 1015 ◽  
pp. 377-380
Author(s):  
Tao Chen ◽  
Ying Chen ◽  
Yin Zhou ◽  
Hong Chen
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
First Principles ◽  
Heusler Alloy ◽  
Density Functional ◽  
Magnetic Moments ◽  
Surface States ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Functional Theory

Using the first-principles calculations within density functional theory (DFT), we investigated the electronic and magnetic properties of (100) surface of inverse Heusler alloy Mn2CoSb with five different terminations. Our work reveals that the surface Mn atom moves to vacuum while surface Co atom moves to slab. Moreover, duo to the reason that the surface atom lost half of the nearest atoms with respect to the bulk phase, resulting in the decrease of hybridization, the atom-resolved spin magnetic moments of surface atoms are enhanced. Further investigation on DOS and PDOS showed that half-metallicity was preserved only in SbSb-termination while was destroyed in MnCo-, MnSb-, MnMn-, and CoCo-termination due to the appearance of surface states.

Atomic structures and electronic properties of Ta-doped 2H-NbSe2

RSC Advances ◽  
2014 ◽  
Vol 4 (101) ◽  
pp. 57541-57546 ◽  
Author(s):  
Hongping Li ◽  
Shuai Liu ◽  
Lin Chen ◽  
Jun Wu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
First Principles Calculations ◽  
Atomic Structures ◽  
The Impact ◽  
Ta Doping

First-principles calculations are conducted to investigate the impact of Ta doping on the atomistic structures and electronic properties of the technologically relevant 2H-NbSe2.

First-Principles Study of Nanofacet Formation on 4H-SiC(0001) Surface

2014 ◽  
Vol 778-780 ◽  
pp. 201-205
Author(s):  
Keisuke Sawada ◽  
Jun Ichi Iwata ◽  
Atsushi Oshiyama
Keyword(s):  
Surface Energy ◽  
Total Energy ◽  
First Principles ◽  
Atomic Layer ◽  
First Principles Calculations ◽  
Atomic Structures ◽  
First Principles Study ◽  
Energy Variation ◽  
The Difference ◽  
Facet Formation

We perform the first-principles calculations on the 4H-SiC(0001) surface and clarify the mechanism of the facet formation. We first identify atomic structures of single-, double- and quadribilayer steps and find that the single-bilayer (SB) step has the lowest total energy among these three step structures. Then, we reveal that the nanofacet consisting of SB steps is more energetically stable than the equally spaced SB step and the surface-energy variation caused by the difference of stacking sequences of the bi-atomic layer near the surface is an important factor of the facet formation.

Defect structures of the Cr2O3(11-20) surface: Effect of electron beam irradiation

2021 ◽  
Author(s):  
Wandong Xing ◽  
Haozhi Sha ◽  
Fanyan Meng ◽  
Rong Yu
Keyword(s):  
Electron Microscopy ◽  
First Principles ◽  
Electron Beam Irradiation ◽  
Surface Effect ◽  
Defect Structures ◽  
First Principles Calculations ◽  
Beam Irradiation ◽  
Atomic Structures ◽  
Transmission Electron ◽  
Aberration Corrected

We have revealed the atomic structures and stability of the (11-20) surface of single crystal Cr2O3 combining aberration corrected transmission electron microscopy and first-principles calculations. It is found that the...

scholarly journals Spin-polarized two-dimensional electron/hole gases on LiCoO$_2$ layers.

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Santosh Kumar Radha ◽  
Walter R. L. Lambrecht
Keyword(s):  
First Principles ◽  
Tight Binding ◽  
Surface States ◽  
Computational Results ◽  
First Principles Calculations ◽  
Dimensional Electron ◽  
Electron Hole ◽  
Spin Polarized ◽  
Binding Models ◽  
Bulk Band

First-principles calculations show the formation of a 2D spin polarized electron (hole) gas on the Li (CoO_22) terminated surfaces of finite slabs down to a monolayer, in remarkable contrast with the bulk band structure, which is stabilized by Li donating its electron to the CoO_22 layer forming a Co-d-t_{2g}^6d−t2g6 insulator. By mapping the first-principles computational results to a minimal tight-binding models corresponding to a non-chiral 3D generalization of the quadripartite Su-Schrieffer-Heeger (SSH4) model and symmetry analysis, we show that these surface states have topological origin.

scholarly journals Obvious Surface States Connecting to the Projected Triple Points in NaCl’s Phonon Dispersion

2021 ◽  
Vol 9 ◽  
Author(s):  
Li Zhang ◽  
Fang Fang ◽  
Lixin Cheng ◽  
Huiming Lin ◽  
Kai Wang
Keyword(s):  
Computer Technology ◽  
Triple Point ◽  
First Principles ◽  
Phonon Dispersion ◽  
Surface States ◽  
Theoretical Chemistry ◽  
First Principles Calculations ◽  
Nodal Lines ◽  
Topological Materials ◽  
Speed And Accuracy

With the development of computer technology and theoretical chemistry, the speed and accuracy of first-principles calculations have significantly improved. Using first-principles calculations to predict new topological materials is a hot research topic in theoretical and computational chemistry. In this work, we focus on a well-known material, sodium chloride (NaCl), and propose that the triple point (TP), quadratic contact triple point (QCTP), linear and quadratic nodal lines can be found in the phonon dispersion of NaCl with Fm3¯ m type structure. More importantly, we propose that the clear surface states connected to the projected TP and QCTP are visible on the (001) surface. It is hoped that further experimental investigation and verification for these properties as mentioned above.

Light Emission Induced by the Indium Distribution in InGaN Nanowires

2013 ◽  
Vol 815 ◽  
pp. 148-153
Author(s):  
Jun Jie Shi ◽  
Tie Cheng Zhou ◽  
Hong Xia Zhong ◽  
Xin He Jiang ◽  
Pu Huang
Keyword(s):  
First Principles ◽  
Electronic Structures ◽  
Light Emission ◽  
Optical Transition ◽  
Laser Diodes ◽  
Optoelectronic Devices ◽  
Surface States ◽  
First Principles Calculations ◽  
Light Emitting ◽  
Interband Optical Transition

The InGaN nanowires (NWs) have attracted intense attention for their huge potential in applications such as light emitting diodes, laser diodes and solar cells. Although lots of work are focused on improving their optical performance, little is known about the influence of the In distribution and the surface states on the microscopic light emission mechanism. In order to give an atomic level understanding, we investigate the electronic structures of the wurtziteGa-rich InGaN NWs with different In distributions using first-principles calculations. We find that the In-atoms are apt to distribute on the surface of the NWs and the short surface In-N chains can be easily formed. For the unsaturated NWs, several new bands are induced by the surface states, which can be modified by the surface In microstructures. The randomly formed surface In-N chains can highly localize the electrons/holes at the band edges and dominate the interband optical transition. For the saturated NWs, the band edges are determined by the inner atoms. Our work is useful to improve the performance of the InGaN NW-based optoelectronic devices.

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