scholarly journals Strain-induced conduction-band spin splitting in GaAs from first-principles calculations

2008 ◽  
Vol 78 (7) ◽  
Author(s):  
Athanasios N. Chantis ◽  
Manuel Cardona ◽  
Niels E. Christensen ◽  
Darryl L. Smith ◽  
Mark van Schilfgaarde ◽  
...  
Keyword(s):  
Conduction Band ◽  
First Principles ◽  
Spin Splitting ◽  
First Principles Calculations

scholarly journals Spin–valley Hall phenomena driven by Van Hove singularities in blistered graphene

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
M. Umar Farooq ◽  
Arqum Hashmi ◽  
Tomoya Ono ◽  
Li Huang
Keyword(s):  
First Principles ◽  
Opposite Sign ◽  
Spin Splitting ◽  
First Principles Calculations ◽  
Van Hove Singularities ◽  
Spin Degree ◽  
Hall Effects ◽  
Back Scattering ◽  
Structural Deformations ◽  
Spin Momentum

AbstractUsing first-principles calculations, we investigate the possibility of realizing valley Hall effects (VHE) in blistered graphene sheets. We show that the Van Hove singularities (VHS) induced by structural deformations can give rise to interesting spin–valley Hall phenomena. The broken degeneracy of spin degree of freedom results in spin-filtered VH states and the valley conductivity have a Hall plateau of ±e2/2h, while the blistered structures with time-reversal symmetry show the VHE with the opposite sign of $$\sigma _{xy}^{K/K^{\prime}}$$ σ x y K / K ′ (e2/2h) in the two valleys. Remarkably, these results show that the distinguishable chiral valley pseudospin state can occur even in the presence of VHS induced spin splitting. The robust chiral spin–momentum textures in both massless and massive Dirac cones of the blistered systems indicate significant suppression of carrier back-scattering. Our study provides a different approach to realize spin-filtered and spin-valley contrasting Hall effects in graphene-based devices without any external field.

Nitrogen-induced magnetism in stannates from first-principles calculations

2016 ◽  
Vol 30 (32) ◽  
pp. 1650236
Author(s):  
Wen-Zhi Xiao ◽  
Bo Meng ◽  
Hai-Qing Xu ◽  
Qiao Chen ◽  
Ling-Ling Wang
Keyword(s):  
Magnetic Properties ◽  
Spin Polarization ◽  
First Principles ◽  
Short Range ◽  
Formation Energy ◽  
Spin Splitting ◽  
Coupling Mechanism ◽  
First Principles Calculations ◽  
Nitrogen Doped ◽  
Perovskite Type

First-principles calculations have been used to comparatively investigate electronic and magnetic properties of nitrogen-doped (N-doped) nonmagnetic semiconductor perovskite-type stannate (MSnO3, M = Ca, Sr, Ba). A total magnetic moment of 1.0 [Formula: see text] induced by N is found in MSnO3 supercell with one N dopant. The spontaneous polarization mainly originates from spin splitting on [Formula: see text] state of N. The medium-sized formation energy shows that the N-doped MSnO3 can be realized experimentally under the metal-rich environments, but the clustering tendency and short-range coupling imply that the stannate matrices are unsuitable for magnetizing by substituting N for O. Our study offers a fresh sight of spontaneous spin polarization in [Formula: see text] magnetism. The FM coupling in N-doped MSnO3 should be attributed to the hole-mediated [Formula: see text]–[Formula: see text] coupling mechanism.

scholarly journals Transformation of the Topological Phase and the Edge Modes of Double-Bilayer Bismuthene with Inter-Bilayer Spacing

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 266 ◽  
Author(s):  
Huanzhi Hu ◽  
Zhibin Shi ◽  
Peng Wang ◽  
Weiping Zhou ◽  
Tai-Chang Chiang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Valence Band ◽  
Conduction Band ◽  
Topological Insulator ◽  
First Principles ◽  
Topological Phase ◽  
First Principles Calculations ◽  
Topological Phase Transition ◽  
Band Inversion ◽  
Band Insulator

The transformations of the topological phase and the edge modes of a double-bilayer bismuthene were investigated with first-principles calculations and Green’s function as the inter-bilayer spacing increased from 0 Å to 10 Å. At a critical spacing of 2 Å, a topological phase transition from a topological insulator to a band insulator resulting from a band inversion between the highest valence band and the second lowest conduction band, was observed, and this was understood based on the particular orbital characters of the band inversion involved states. The edge modes of double-bilayer bismuthene survived the phase transition. When d was 2 Å < d < 4 Å, the interaction between the edge modes of two separated bismuthene bilayers induced an anti-crossing gap and resulted in a trivial band connection. At and beyond 4 Å, the two bilayers behavior decoupled entirely. The results demonstrate the transformability of the topological phase and the edge modes with the inter-bilayer spacing in double-bilayer bismuthene, which may be useful for spintronic applications.

Effects of Strain on Optical Properties of BiFeO3: A First-Principles Study

2016 ◽  
Vol 703 ◽  
pp. 224-229
Author(s):  
Zhen Ye Zhu ◽  
Si Qi Wang ◽  
Qian Wang
Keyword(s):  
Optical Properties ◽  
Conduction Band ◽  
First Principles ◽  
State Density ◽  
Low Energy ◽  
Optical Absorption Coefficient ◽  
First Principles Calculations ◽  
Photovoltaic Application ◽  
Density Peaks ◽  
Optical Applications

In order to investigate the effects of strain on optical properties of BiFeO3, electronic structure, dielectric properties and optical properties of BiFeO3 under different strain conditions were performed by first-principles calculations. Results show that the optical spectra of BiFeO3 is mainly determined by the contributions from transition from valence band O 2p to conduction band Fe 3d levels or even higher conduction band Bi 6s states in the low-energy region. Compared with equilibrium state, state density peaks shift to left side and state density peaks become broader and lower, and band gap becomes smaller under strain states. Furthermore, strain increases optical absorption coefficient peaks, energy loss coefficient peaks and reflectivity coefficient peaks, and extinction coefficient peaks, exhibiting that optical properites of BiFeO3 is improved under strain states. Our research provides theoretical guidance for future optical applications of BiFeO3, especially photovoltaic application.

The electronic structure and spin–orbit-induced spin splitting in antimonene with vacancy defects

RSC Advances ◽  
2016 ◽  
Vol 6 (70) ◽  
pp. 66140-66146 ◽  
Author(s):  
Lifang Yang ◽  
Yan Song ◽  
Wenbo Mi ◽  
Xiaocha Wang
Keyword(s):  
Electronic Structure ◽  
Electronic Properties ◽  
First Principles ◽  
Spin Splitting ◽  
Spin Orbit ◽  
First Principles Calculations ◽  
Vacancy Defects

We study the geometric, electronic properties, and spin splitting in monovacancy (MV) and divacancy (DV) antimonene with five different models using first-principles calculations.

Gadolinium and Oxygen co-doping of Gallium Nitride: an LSDA + U study

2006 ◽  
Vol 955 ◽  
Author(s):  
Walter R. L. Lambrecht ◽  
Paul Larson
Keyword(s):  
Gallium Nitride ◽  
Conduction Band ◽  
Magnetic Moment ◽  
First Principles ◽  
Magnetic Moments ◽  
Active Role ◽  
Spin Splitting ◽  
Co Doping ◽  
Moment Estimates

ABSTRACTResults of first-principles supercell calculations for Gd impurities, with and without O-impurities in the same cell are presented. The possibility of colossal magnetic moments, as reported by Dhar et al., [Phys. Rev. Lett. 94, 037205 (2005)] is discussed in view of the results. Particular attention is paid to the size of the conduction band spin splitting, induced by Gd. It is argued that O plays a more active role than merely providing the electrons leading to the magnetic moment. Estimates are made of the splitting of the conduction band required to explain the occurrence of colossal magnetic moments.

scholarly journals First-principles calculations on CuInSe2/AlP heterostructures

2020 ◽  
Vol 8 (14) ◽  
pp. 4732-4742 ◽  
Author(s):  
Pingping Jiang ◽  
Marie-Christine Record ◽  
Pascal Boulet
Keyword(s):  
Conduction Band ◽  
Conversion Efficiency ◽  
First Principles ◽  
Band Offset ◽  
First Principles Calculations ◽  
Conduction Band Offset

Heterostructures based on a CuInSe2 absorber with an AlP buffer have a 12 meV conduction band offset and achieved 27.39% of conversion efficiency.

Importance of SiC Stacking to Interlayer States at the SiC/SiO2 Interface

2016 ◽  
Vol 858 ◽  
pp. 457-460
Author(s):  
Christopher James Kirkham ◽  
Tomoya Ono
Keyword(s):  
Electronic Structure ◽  
Conduction Band ◽  
First Principles ◽  
Local Structure ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Conduction Band Edge ◽  
First Principles Calculations

We investigated the effect of SiC stacking on the 4H-SiC/SiO2 interface via first principles calculations. Interlayer states are observed along the SiC conduction band edge, and are affected by the local structure at the interface. The location of these states changes depending on which of two lattice sites, h or k is at the interface. This difference is important for SiC based metal-oxide-semiconductor field-effect transistors which rely on the electronic structure of the conduction band.

scholarly journals Tuning Electronic Properties of the SiC-GeC Bilayer by External Electric Field: A First-Principles Study

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 309
Author(s):  
Min Luo ◽  
Bin Yu ◽  
Yu-e Xu
Keyword(s):  
Band Structure ◽  
Electric Field ◽  
Fermi Level ◽  
Electronic Properties ◽  
External Electric Field ◽  
Valence Band ◽  
Conduction Band ◽  
First Principles ◽  
First Principles Calculations ◽  
Direct Bandgap

First-principles calculations were used to investigate the electronic properties of the SiC/GeC nanosheet (the thickness was about 8 Å). With no electric field (E-field), the SiC/GeC nanosheet was shown to have a direct bandgap of 1.90 eV. In the band structure, the valence band of the SiC/GeC nanosheet was mainly made up of C-p, while the conduction band was mainly made up of C-p, Si-p, and Ge-p, respectively. Application of the E-field to the SiC/GeC nanosheet was found to facilitate modulation of the bandgap, regularly reducing it to zero, which was linked to the direction and strength of the E-field. The major bandgap modulation was attributed to the migration of C-p, Si-p, and Ge-p orbitals around the Fermi level. Our conclusions might give some theoretical guidance for the development and application of the SiC/GeC nanosheet.

Sign in / Sign up

Export Citation Format

Share Document