Proposal on Tunneling Effect between Quantum Hall States

In the integer and fractional quantum Hall effects, the electric current flows through a thin layer under the strong magnetic field. The diagonal resistance becomes very small at integer and specific fractional filling factors where the electron scatterings are very few. Accordingly the coherent length is large and therefore a tunneling effect of electrons may be observed. We consider a new type of a quantum Hall device which has a narrow potential barrier in the thin layer. Then the electrons flow with tunneling effect through the potential barrier. When the oscillating magnetic field is applied in addition to the constant field, the voltage steps may appear in the curve of voltage V versus electric current I. If the voltage steps are found in the experiment, it is confirmed that the 2D electron system yields the same phenomenon as that of the ac-Josephson effect in a superconducting system. Furthermore the step V is related to the transfer charge Q as V = (hf)/Q where f is the frequency of the oscillating field and h is the Planck constant. Then the detection of the step V determines the transfer charge Q. The ratio Q/e (e is the elementary charge) clarifies the origin of the transfer charge. Many conditions are required for us to observe the tunneling phenomenon. The conditions are examined in details in this article.

Quantum confinement effects and source-to-drain tunneling in ultra-scaled double-gate silicon n-MOSFETs

By using the linear combination of bulk band （LCBB） method incorporated with the top of the barrier splitting （TBS） model, we present a comprehensive study on the quantum confinement effects and the source-to-drain tunneling in the ultra-scaled double-gate （DG） metal-oxide semiconductor field-effect transistors （MOSFETs）. A critical body thickness value of 5 nm is found, below which severe valley splittings among different X valleys for the occupied charge density and the current contributions occur in ultra-thin silicon body structures. It is also found that the tunneling current could be nearly 100% with an ultra-scaled channel length. Different from the previous simulation results, it is found that the source-to-drain tunneling could be effectively suppressed in the ultra-thin body thickness （2.0 nm and below） by the quantum confinement and the tunneling could be suppressed down to below 5% when the channel length approaches 16 nm regardless of the body thickness.

Quantum Standing Waves and Tunneling Through a Finite Range Potential

We consider a time independent one dimensional finite range and repulsive constant potential barrier between two impenetrable walls. For a nonrelativistic massive particle projected towards the potential with energies less than the barrier and irrespective of the spatial positioning of the potential allowing for quantum tunneling, analytically we solve the corresponding Schrodinger equation. For a set of suitable parameters utilizing Mathematica we display the wave functions along with their associated probabilities for the entire region. We investigate the sensitivity of the probability distributions as a function of the potential range and display a gallery of our analysis. We extend our analysis for bound state particles confined within constant attractive potentials.

Tunneling effect in cavity-resonator-coupled arrays

The quantum tunneling effect （QTE） in a cavity-resonator-coupled （CRC） array was analytically and numerically investigated. The underlying mechanism was interpreted by treating electromagnetic waves as photons, and then was generalized to acoustic waves and matter waves. It is indicated that for the three kinds of waves, the QTE can be excited by cavity resonance in a CRC array, resulting in sub-wavelength transparency through the narrow splits between cavities. This opens up opportunities for designing new types of crystals based on CRC arrays, which may find potential applications such as quantum devices, micro-optic transmission, and acoustic manipulation.

New Derivation of Simple Josephson Effect Relation Using New Quantum Mechanical Equation

A relation of the Josephson current density equation is successfully derived;this is done through a new derivation of the equation of quantum by neglecting kinetic Newtonian term in the energy expression.

Analytical Modeling of Quantum Mechanical Tunneling in Germanium Nano-MOSFETS

A simple analytical model has been developed to study quantum mechanical effects （QME） in a germanium substrate MOSFET （metal oxide semiconductor field effect transistor）, which includes gate oxide tunneling considering the energy quantization effects in the substrate. Some alternate high dielectric constant materials to reduce the tunneling have also been studied. By comparing with the numerically reported results, the results match well with the existing reported work.

Analytical Modeling of Source-to-Drain Tunneling in Nanoscale Silicon MOSFET

Sub-10-nm bulk n-MOSFET （metal-oxide -semiconductor field effect transistor） direct source-to- drain tunneling current density using Wentzel- Krammers-Brillouin 0NKB） transmission tunneling theory has been simulated. The dependence of the source-to-drain tunneling current on channel length and barrier height is examined. Inversion layer quantization, band-gap narrowing, and drain induced barrier lowering effects have been included in the model. It has been observed that the leakage current density increases severely below 4 nm channel lengths, thus putting a limit to the scaling down of the MOSFETs. The results match closely with the numerical results already reported in literatures.

Schwarzschild Quantum Light Geodesics Metric: A Pair of BH-Inner WH

In this article we hypothesized that the arrow of time and space evolve in a discontinuous way in the form of quanta (t=ntp, s=mlp). We applied this reasoning to the light geodesics of Schwarzschild’s metric (dsmin=lp) and obtained different characteristics of the BH. Indeed, quantum light geodesics show that inside the BH a WH is formed and the mass (energy) is not directing towards the singularity r→0 but rather around the BH near the EH as a thick skin (tickness ). The total relativistic energy invariant is satisfied for the entire route of the photons. Subsequently, as mass (energy) is found directly at the EH, we applied the quantum tunnel effect in simple semi-classical analysis, and we obtained that particles like protons can leave the EH and that the energy associated with them is in the order of magnitude of Hawking’s radiation. However, the energy of the protons is not necessarily identified with that of the black body (photonic or electromagnetic). Finally, it would be interesting to see the impacts of this quantum light geodesics (dsmin=lp) on other cases like Kerr’s metric.

Investigation of gate current in nano-scale MOSFETs by Monte Carlo solution of quantum Boltzmann equation

This paper investigates gate current through ultra-thin gate oxide of nano-scale metal oxide semiconductor field effect transistors （MOSFETs）, using two-dimensional （2D） full-band self-consistent ensemble Montc Carlo method based on solving quantum Boltzmann equation. Direct tunnelling, Fowler-Nordheim tunnelling and thermionic emission currents have been taken into account for the calculation of total gate current. The 2D effect on the gate current is investigated by including the details of the energy distribution for electron tunnelling through the barrier. In order to investigate the properties of nano scale MOSFETs, it is necessary to simulate gate tunnelling current in 2D including non-equilibrium transport.

Tight-binding study of quantum transport in nanoscale GaAs Schottky MOSFET

This paper explores the band structure effect to elucidate the feasibility of an ultra-scaled GaAs Schottky MOSFET （SBFET） in a nanoscale regime. We have employed a 20-band sp3dSs＊ tight-binding （TB） approach to compute E - K dis- persion. The considerable difference between the extracted effective masses from the TB approach and bulk values implies that quantum confinement affects the device performance. Beside high injection velocity, the ultra-scaled GaAs SBFET suffers from a low conduction band DOS in the F valley that results in serious degradation of the gate capacitance. Quan- tum confinement also results in an increment of the effective Schottky barrier height （SBH）. Enhanced Schottky barriers form a double barrier potential well along the channel that leads to resonant tunneling and alters the normal operation of the SBFET. Major factors that may lead to resonant tunneling are investigated. Resonant tunneling occurs at low temperatures and low drain voltages, and gradually diminishes as the channel thickness and the gate length scale down. Accordingly, the GaAs （100） SBFET has poor ballistic performance in nanoscale regime.

Spin-valley-dependent transport and giant tunneling magnetoresistance in silicene with periodic electromagnetic modulations

The transport property of electrons tunneling through arrays of magnetic and electric barriers is studied in silicene. In the tunneling transmission spectrum, the spin-valley-dependent filtered states can be achieved in an incident energy range which can be controlled by the electric gate voltage. For the parallel magnetization configuration, the transmission is asymmetric with respect to the incident angle θ, and electrons with a very large negative incident angle can always transmit in propagating modes for one of the spin-valley filtered states under a certain electromagnetic condition. But for the antiparallel configuration, the transmission is symmetric about θ and there is no such transmission channel. The difference of the transmission between the two configurations leads to a giant tunneling magnetoresistance （TMR） effect. The TMR can reach to 100% in a certain Fermi energy interval around the electrostatic potential. This energy interval can be adjusted significantly by the magnetic field and/or electric gate voltage. The results obtained may be useful for future valleytronic and spintronic applications, as well as magnetoresistance device based on silicene.

基于量子隧道效应的量子随机数发生器研究进展

从2000年开始,量子随机数发生器(Quantum Random Number Generator,QRNG)逐渐受到广泛关注。与算法或经典物理系统随机数发生器相比,QRNG的量子随机源不由确定性的算法或方程描述,仅由波函数进行概率描述,具有内禀随机性。目前,QRNG方案大多基于光子体系。近年来,基于电子体系的量子随机数发生器(electronic Quantum Random Number Generator,eQRNG)方案相继被提出。与光子QRNG相比,eQRNG没有电-光-电转换,有效避免了转换过程中经典噪声的影响,在随机性上具有更大优势,且结构简单、系统稳定,与半导体工艺兼容,具有可集成性。基于此,通过介绍基于量子隧道效应的eQRNG研究进展,包括基于隧道二极管的eQRNG、基于范德瓦尔斯异质结的eQRNG与基于雪崩光电二极管的eQRNG等,阐述了eQRNG在随机性与量子性上的独特优势。

Flux quantum tunneling effect and its influence on the experimental critical current density

By using magnetic sweeping method, the temperature and magnetic field dependencies of the experimental current density and the normalized relaxation rate have been obtained. The true critical current density corresponding to the zero activation energy has been carried out based on the collective-pinning and the thermally-activated flux motion models, and therefore the influences of the quantum tunneling effect and the thermal activation effect on the experimental critical current density are distinguished. It is found that, with temperature lower than 10 K, the relaxation rate will not drop to zero when T approaches zero K because of the occurrence of the flux quantum tunneling. This additional flux motion further reduces the experimental critical current density j making it saturated with lowering temperature.

A pure quantum mechanical theory of parity effect in tunneling and evolution of spins

In recent years, the spin parity effect in magnetic macroscopic quantum tunneling has attracted extensive attention. Using the spin coherent-state path-integral method it is shown that if the HamiltonianH of a single-spin system hasM - fold rotational symmetry around z-axis, the tunneling amplitude 〈?S|e Ht |S〉 vanishes when S, the quantum number of spin, is not an integer multiple ofM/2, where |m〉 (m=-S, -S +1, ?, S) are the eigenstates of Sz. Not only is a pure quantum mechanical approach adopted to the above result, but also is extended to more general cases where the quantum system consists ofN spins, the quantum numbers of which can take any values, including the single-spin system, ferromagnetic particle and antiferromagnetic particle as particular instances, and where the states involved are not limited to the extreme ones. The extended spin parity effect is that if the Hamiltonian ? of the system ofN spins also has the above symmetry, then 〈m′N?m′2 m′1|e?H t |m 1 m 2?m N vanishes when ∑ i=1 N (m i?m′1) not an integer multiple ofM, where |m 1 m 2?m N〉=∏ α=1 N |m a 〉 are the eigenstates of S a z . In addition, it is argued that for large spin the above result, the so-called spin parity effect, does not mean the quenching of spin tunneling from the direction of ⊕-z to that of ±z.

量子路径积分算法及其在大地电磁反演中的应用

常规非线性反演方法虽然对初始模型的依赖大为减弱,但局部收敛现象和计算速度慢仍然是瓶颈.本文提出了一种新的反演方法——量子路径积分算法(Quantum Path Integral Algorithm,简称QPIA).该方法引入量子力学的横向场、传播子等概念,并充分利用量子隧穿效应,大大提高反演的效率,具体是通过对反演目标函数的构建,并以Feynman的传播子来构成模型的接收概率来实现.在对一维大地电磁模型和实际数据进行试验后,表明该方法比常规反演方法更能够精确、稳定和快速地逼近真实模型.

复合型导电高分子材料导电机理研究及电阻率计算

综述了复合型导电高分子材料的导电机理，描述了电子的微观传输过程；总结了计算电阻率的两种常用方法──渗流理论和量子力学隧道效应，分析了计算电阻率的各种模型和计算方法。

填充复合型导电高分子材料导电机理及导电性能影响因素研究概况

采用渗流理论、量子力学隧道效应理论和场致发射效应等理论,对填充复合型导电高分子材料的导电机理进行了分析介绍;从聚合物的结构、导电填料的种类、性能、用量、复合材料制备方法、加工及使用条件等因素,分析了影响填充复合型导电高分子材料导电性能的主要因素。

基于场致发射和量子隧道效应的镍粉填充压敏复合材料

通过测试不同种类、不同掺量镍粉复合水泥基材料的电阻率和受力时的电阻率变化规律,并结合镍粉颗粒状态和表面形貌的扫描电镜观察,探讨了镍粉水泥基复合材料的导电机理和压敏性产生机理。研究结果表明:刺球状镍粉掺量(体积分数)为15%、20%和25%的水泥基复合材料的导电性和压敏性依次提高;链状镍粉复合水泥基材料的导电性优于球状镍粉水泥基复合材料;刺球状镍粉复合水泥基材料的导电性优于表面光滑的球状镍粉水泥基复合材料。由此可见,镍粉水泥基复合材料的导电性和压敏性与镍粉的颗粒状态、表面形貌和掺量密切相关,刺球状镍粉水泥基复合材料具有良好导电性和压敏性是由场致发射效应和量子隧道效应所致。

单电子晶体管(SET)及其应用

当电子器件的尺寸接近纳米尺度时,量子效应对器件工作的影响变得格外重要,就需要采用具有新机理的晶体管结构,单电子晶体管(SET)就是其中一个典型的结构。文中对比传统晶体管(MOSFET)的工作原理,分析了单电子晶体管SET的工作机理,简要概述了SET的一些应用。

量子计算机的商业化进展及对信息安全的挑战

通用量子计算机器件进展缓慢,对实用化1 024 bit的RSA密码的破译尚不构成威胁,现代密码依旧是安全的。首次提出了对Shor算法的改进应考虑量子器件约束,第一和第二量子寄存器器件要求需从设计理论的1 000~2 000 Qubit降至100 Qubit以下。基于量子人工智能的专用量子计算机的商业化进展迅猛,已列为应对美国国家战略计算计划的新一代计算思想,在机器学习和模式识别领域应用广泛,不能忽视其对互联网大数据信息安全的影响。首次提出了将量子计算机应用于密码设计,从量子人工智能角度提出了国外尚未开展的量子计算密码研究。