Temperature Dependence of Two-Dimensional Spin Anisotropies

1989 ◽  
Vol 151 ◽  
Author(s):  
Roy Richter ◽  
Jack G. Gay
Keyword(s):  
Electronic Structure ◽  
Permanent Magnets ◽  
Computer Time ◽  
Essential Property ◽  
Two Dimensional ◽  
High Quality ◽  
Easy Direction ◽  
Spin Polarized ◽  
Out Of Plane ◽  
Large Anisotropy

ABSTRACTLarge anisotropy energy is an essential property of high quality permanent magnets. In previous work we have calculated the spin polarized electronic structure and anisotropy of monolayers and slabs of Fe, Ni, and V. In this work we calculate the dependence on temperature of the spin anisotropy of a ferromagnetic monolayer of Fe. We find the easy direction of magnetization is not sensitive to the temperature; the variations calculated here are likely too small to be observed. It is perpendicular to the plane of the surface for both low and high temperatures. The calculations become progressively more ill-behaved as the temperatures are lowered and require more computer time for satisfactory convergence.For Fe/Cu {100}, we find the spins always prefer to point out of plane. Experimental results in general are consistent with this view, although the systems seem to be difficult to prepare.

Fully spin-polarized Weyl fermions and in/out-of-plane quantum anomalous Hall effects in a two-dimensional d0 ferromagnet

Nanoscale ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 5901-5909
Author(s):  
Lei Jin ◽  
Lirong Wang ◽  
Xiaoming Zhang ◽  
Ying Liu ◽  
Xuefang Dai ◽  
...  
Keyword(s):  
Topological Phases ◽  
Two Dimensional ◽  
Magnetization Direction ◽  
Hall Effects ◽  
Spin Polarized ◽  
Out Of Plane ◽  
Weyl Fermions

A YN2 monolayer can realize multiple topological phases, determined based on the magnetization direction. In particular, the in-plane QAHE can be realized in a d0 ferromagnet.

Electronic structure of two-dimensional electron gases at differently prepared indium arsenide surfaces

2021 ◽  
Vol 555 ◽  
pp. 149516
Author(s):  
Jacek J. Kolodziej ◽  
Dawid Wutke ◽  
Jakub Lis ◽  
Natalia Olszowska
Keyword(s):  
Electronic Structure ◽  
Indium Arsenide ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Electron Gases

scholarly journals Global optimization of an encapsulated Si/SiO$$_2$$ L3 cavity with a 43 million quality factor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. P. Vasco ◽  
V. Savona
Keyword(s):  
Global Optimization ◽  
Photonic Crystal ◽  
Quality Factor ◽  
State Of The Art ◽  
Optimization Strategy ◽  
High Quality ◽  
Optimal Value ◽  
Out Of Plane ◽  
Fabrication Tolerances ◽  
Structural Imperfections

AbstractWe optimize a silica-encapsulated silicon L3 photonic crystal cavity for ultra-high quality factor by means of a global optimization strategy, where the closest holes surrounding the cavity are varied to minimize out-of-plane losses. We find an optimal value of $$Q_c=4.33\times 10^7$$ Q c = 4.33 × 10 7 , which is predicted to be in the 2 million regime in presence of structural imperfections compatible with state-of-the-art silicon fabrication tolerances.

scholarly journals High performance self-powered photodetector based on 1D Te-2D WS2 mixed-dimensional heterostructure

2021 ◽  
Author(s):  
Lixiang Han ◽  
Mengmeng Yang ◽  
Peiting Wen ◽  
Wei Gao ◽  
nengjie huo ◽  
...  
Keyword(s):  
High Performance ◽  
Van Der Waals ◽  
Sharp Interface ◽  
Two Dimensional ◽  
High Quality ◽  
One Dimensional ◽  
Self Powered

One dimensional (1D)-two dimensional (2D) van der Waals (vdWs) mixed-dimensional heterostructures with advantages of atomically sharp interface, high quality and good compatibility have attracted tremendous attention in recent years. The...

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

Biaxial strain, electric field and interlayer distance-tailored electronic structure and magnetic properties of two-dimensional g-C3N4/Li-adsorbed Cr2Ge2Te6 van der Waals heterostructures

2021 ◽  
Vol 23 (10) ◽  
pp. 6171-6181
Author(s):  
Yaoqi Gao ◽  
Baozeng Zhou ◽  
Xiaocha Wang
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Electric Field ◽  
Van Der Waals ◽  
Interlayer Distance ◽  
Two Dimensional ◽  
Biaxial Strain ◽  
Van Der Waals Heterostructures

It is found that the biaxial strain, electric field and interlayer distance can effectively modulate the electronic structure and magnetic properties of two-dimensional van der Waals heterostructures.

scholarly journals Electronic structure of monolayer antimonene nanoribbons under out-of-plane and transverse bias

2018 ◽  
Vol 2 (11) ◽  
Author(s):  
Edo van Veen ◽  
Jin Yu ◽  
Mikhail I. Katsnelson ◽  
Rafael Roldán ◽  
Shengjun Yuan
Keyword(s):  
Electronic Structure ◽  
Out Of Plane

scholarly journals Manipulation of hot carrier cooling dynamics in two-dimensional Dion–Jacobson hybrid perovskites via Rashba band splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jun Yin ◽  
Rounak Naphade ◽  
Partha Maity ◽  
Luis Gutiérrez-Arzaluz ◽  
Dhaifallah Almalawi ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Phonon Scattering ◽  
Transient Absorption Spectroscopy ◽  
Band Model ◽  
Two Dimensional ◽  
Spintronic Devices ◽  
Hot Carrier ◽  
Band Splitting ◽  
Perovskite Materials ◽  
Spin Polarized

AbstractHot-carrier cooling processes of perovskite materials are typically described by a single parabolic band model that includes the effects of carrier-phonon scattering, hot phonon bottleneck, and Auger heating. However, little is known (if anything) about the cooling processes in which the spin-degenerate parabolic band splits into two spin-polarized bands, i.e., the Rashba band splitting effect. Here, we investigated the hot-carrier cooling processes for two slightly different compositions of two-dimensional Dion–Jacobson hybrid perovskites, namely, (3AMP)PbI4 and (4AMP)PbI4 (3AMP = 3-(aminomethyl)piperidinium; 4AMP = 4-(aminomethyl)piperidinium), using a combination of ultrafast transient absorption spectroscopy and first-principles calculations. In (4AMP)PbI4, upon Rashba band splitting, the spin-dependent scattering of hot electrons is responsible for accelerating hot-carrier cooling at longer delays. Importantly, the hot-carrier cooling of (4AMP)PbI4 can be extended by manipulating the spin state of the hot carriers. Our findings suggest a new approach for prolonging hot-carrier cooling in hybrid perovskites, which is conducive to further improving the performance of hot-carrier-based optoelectronic and spintronic devices.

scholarly journals Van der Waals electride: Toward intrinsic two-dimensional ferromagnetism of spin-polarized anionic electrons

2021 ◽  
pp. 100473
Author(s):  
Hyun Yong Song ◽  
Byung Il Yoo ◽  
Jin-Ho Choi ◽  
Se-Hwang Kang ◽  
Joonho Bang ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Two Dimensional ◽  
Spin Polarized
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