This paper is devoted mainly to mathematical aspects of modeling and simulation of tunnel relaxation of nonequilibrium charged oxide traps located at/near the interface insulator - conductive channel, for instance in irradiated MOS devices. The generic form of the tunnel annealing response function was derived from the rate equation for the charged defect buildup and annealing as a linear superposition of the responses of different defects with different time constants. Using this linear response function, a number of important practical problems are analyzed and discussed. Combined tunnel and thermal or RICN annealing, power-like temporal relaxation after a single ion strike into the gate oxide, are described in context of general approach.
Interfacial Effects of Al-Termination on Spin Transport in Magnetic Tunnel Junctions
实验表明，Co/Al $_2$ O $_3$磁性隧道结（MTJ）中的隧道电流是正自旋极化的，这与标准隧道理论直观地预期的相反，标准隧道理论给出的自旋极化完全取决于Co层的$E_F$处的态密度（DOS）。在这里，我们报告的理论结果，给出一个积极的隧道自旋极化和隧道磁电阻（TMR）是在良好的协议与实验。从密度泛函理论（DFT）的计算，富铝界面MTJ与原子级的障碍被证明有一个积极的极化DOS界面附近。我们还提供了一个原子模型的计算，它给出了见解的正极化的来源。一个层和自旋相关的有效质量模型，使用从DFT结果提取的值，然后被用来计算隧道电流，这表明积极的自旋极化。最后，我们从隧穿自旋极化率计算了TMR，与实验结果符合得很好。
The tunnel magnetoresistance (TMR) is one of the most important spintronic phenomena but its reduction at finite temperature is a severe drawback for applications. Here, we reveal a crucial determinant of the drawback, that is, the $s$-$d$ exchange interaction between conduction $s$ and localized $d$ electrons at interfacial ferromagnetic layers. By calculating the temperature dependence of the TMR ratio in Fe/MgO/Fe(001), we show that the obtained TMR ratio significantly decreases with increasing temperature owing to the spin-flip scattering in the $Δ_1$ state induced by the $s$-$d$ exchange …
Tunnel-Barrier-Engineered Ultrafast Demagnetization and Spin Transport in Graphene-Based Heterostructures
S. N. Bose National Center for Basic Sciences（S.N. 玻色基础科学国家中心）；Indian Institute of Science Education and Research Kolkata（加尔各答印度科学与教育研究所）；Uppsala University（乌普萨拉大学）
We theoretically study the tunnel magnetoresistance (TMR) effect in (111)-oriented junctions Co/MgO/Co(111) and Ni/MgO/Ni(111). The Co-based junction is shown to have a TMR ratio over 2000$\%$, which is one order higher than that of the Ni-based one. The high TMR ratio is attributed to the interfacial resonance effect: The interfacial $d$-$p$ antibonding states are formed close to the Fermi level in the majority-spin channel and these states in both interfaces resonate with each other. This differs essentially from the conventional coherent tunneling mechanism of high TMR ratios in Fe(Co)/MgO/…
In this paper, we have built a numerical p-n Si/GaAs heterojunction model using a quantum-mechanical tunneling theory with various quantum tunneling interfacial materials including two-dimensional semiconductors such as hexagonal boron nitride (h-BN) and graphene and ALD-enabled oxide materials such as HfO2, Al2O3, and SiO2. Their tunneling efficiencies and tunneling current with different thicknesses were systematically calculated and compared. Multiphysics modeling was used with the aforementioned tunneling interfacial materials to analyze changes in strain under different temperature condit…
Effect of interfacial Dzyaloshinskii-Moriya interaction in spin dynamics of an Antiferromagnet coupled Ferromagnetic double-barrier Magnetic Tunnel Junction
Edge and Interfacial States in a 2D Topological Insulator:Bi(111) Bilayer on Bi$_{2}$Te$_{2}$Se
利用扫描隧道谱（STS）和第一性原理计算研究了二维拓扑绝缘体Bi（111）双层膜及其边缘的电子态.在解理的Bi $_{2}$ Te $_{2}$ Se晶体上外延生长了具有锯齿形边缘的有序双层膜和岛。计算表明，由于Bi和Bi $_{2}$ Te $_{2}$ Se之间的强相互作用，Bi双层膜的带隙关闭，形成了一个新的但很小的杂化带隙.尽管如此，拓扑性质的Bi双层和拓扑边缘状态被保存只有一个能量转移。边缘增强的局域态密度被STS清晰地识别和可视化，与计算结果吻合得很好。这可以是拓扑边缘态的符号，它对应于量子自旋霍尔态。Bi和Bi $_{2}$ Te $_{2}$ Se之间的界面态也在带隙区域内被识别。这种状态也表现出边缘调制，这是以前解释为拓扑边缘状态的证据[F。Yang等人，物理修订版信函109，016801（2012）]。
Electrically tunable interfacial thermal conduction via electronic structure engineering in ${Au}$/$Bi_{1-x}$$Sb_{x}$ topological insulators
The Ohio State University（俄亥俄州立大学）；Korea Institute of Science and Technology (KIST)（韩国科学技术院）；Korea Advanced Institute of Science and Technology (KAIST)（韩国科学技术院）；Pohang University of Science and Technology (POSTECH)（浦项科技大学）；Carnegie Mellon University（卡内基梅隆大学）；E. O. Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
Superconductivity and magnetism are generally incompatible because of the opposing requirement on electron spin alignment. When combined, they produce a multitude of fascinating phenomena, including unconventional superconductivity and topological superconductivity. The emergence of two-dimensional (2D)layered superconducting and magnetic materials that can form nanoscale junctions with atomically sharp interfaces presents an ideal laboratory to explore new phenomena from coexisting superconductivity and magnetic ordering. Here we report tunneling spectroscopy under an in-plane magnetic field …
Graphene quality indicators obtained by Raman spectroscopy have been correlated to the structural changes of the graphene/Germanium interface as a function of in-vacuum thermal annealing. Specifically, it is found that graphene becomes markedly defected at 650 °C. By combining scanning tunneling microscopy, x-Ray Photoelectron Spectroscopy and Near Edge x-ray Absorption Fine Structure Spectroscopy, we conclude that these defects are due to the release of H_{2} gas trapped at the graphene/Germanium interface. The H_{2} gas was produced following the transition from the as-grown hydrogen-termina…
We present a computational study of the adhesive and structural properties of the Al/Al2O3 interfaces as building blocks of the Metal-Insulator-Metal (MIM) tunnel devices, where electron transport is accomplished via tunnelling mechanism through the sandwiched insulating barrier. The main goal of this paper is to understand, on the atomic scale, the role of the geometrical details in the formation of the tunnel barrier profiles. To provide reliable results, we carefully assess the accuracy of the traditional methods used to examine Al/Al2O3 interfaces. These are the most widely employed exchan…
