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The Temperature Dependences of the Electron-Piezoelectric Potential Phonon Interacting System of Quasi Two Dimensional System in GaN and ZnS
摘要： We investigated theoretically the temperature dependence of the quantum optical transition of quasi 2-Dimensional Landau splitting system, in GaN and ZnS. We apply the Quantum Transport theory (QTR) to the system in the con?nement of electrons by square well con?nement potential. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). Through the analysis of this work, we found the increasing properties of Quantum Transition Line Shapes (QTLSs) and the Quantum Transition Line Widths (QTLWs) of CdS and GaN with the temperature we also found that QTLW, (cid:2)(cid:3)T (cid:4) of ZnS < (cid:2)(cid:3)T (cid:4) of GaN in (cid:5) = 394 (cid:6)m.
关键词： Quantum Transport Theory,Quantum Transition Line Widths (QTLW),Quantum Transition Line Shapes (QTLS),GaN and ZnS,Cyclotron Resonance,Equilibrium Average Projection Scheme (EAPS),Electron Phonon Coupling System
更新于2025-09-23 15:22:29
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Bias-induced chiral current and geometrical blockade in triangular triple quantum dot
摘要： We theoretically investigate the quantum transport properties of a triangular triple quantum dot (TTQD) ring connected to two reservoirs by an analytical derivation and an accurate hierarchical equations-of-motion calculation. We initially demonstrate a bias-induced chiral current under zero magnetic field caused by the coupling between the spin gauge field and spin current in a nonequilibrium TTQD that induces a scalar spin chirality, which lifts the chiral degeneracy and the time inversion symmetry. The chiral current oscillates with the bias within the Coulomb blockade regime, suggesting that the chiral spin qubit can be controlled by purely electrical manipulations. Then, the geometrical blockade of the transport current due to the localization of chiral states is elucidated by spectral function analysis.
关键词： triple quantum dot,quantum transport,chiral current,geometrical blockade
更新于2025-09-23 15:21:01
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A generalised approach to calculate various transport observables for a linear array of series and parallel quantum dots
摘要： A systematic generalised approach to ?nd transport observables for a linear array of different quantum dot (QD) systems has been discussed, using non-equilibrium Green function (NEGF) formalism, in the presence of on-dot Coulomb interaction and inter-dot tunnelling. The equation of motion (EOM) method has been used to derive expressions for Green functions (GFs) within the simplest mean-?eld approximation to tackle the Coulomb correlation term. Starting from the mathematical structures of GFs for single, double and triple quantum dot systems, the expressions for GFs and transport observables have been generalised for the quantum dot systems containing N number of quantum dots in series as well as parallel linear array of dots. Further, the formulae so obtained have been used for numerical calculations of transmission probability and the I –V characteristics of linear arrays of quantum dots in series as well as parallel con?guration containing up to three dots. The results show that, with the increase in number of dots in the scattering region, transmission probability and electron current decrease in series case, while both quantities increase in parallel con?guration of dots. The inter-dot tunnelling leads to the splitting of transmission peaks in double QD system in series case whereas, it induces Fano effect in triple QD system in parallel con?guration.
关键词： quantum dots,Quantum transport,non-equilibrium Green function,Landauer–Buttiker formula,linear array of dots
更新于2025-09-23 15:21:01
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Remarkable negative differential resistance and perfect spin-filtering effects of the indium triphosphide (InP <sub/>3</sub> ) monolayer tuned by electric and optical ways
摘要： Fully spin-polarized current and negative differential resistance (NDR) are two important electronic transport properties for spintronic nanodevices based on two-dimensional materials. Here, we describe both the electric and optical tuning of the spin-polarized electronic transport properties of the indium triphosphide (InP3) monolayer, which is doped with Ge atoms, by using quantum transport calculations. The spin degeneration of the InP3 monolayer is lifted due to the doping of Ge atoms. By applying a small bias voltage, a fully spin-polarized current can be obtained along both the armchair and zigzag directions. Moreover, a remarkable NDR is observed for the current along the zigzag direction, which shows a huge peak-to-valley ratio of 3.1 (cid:2) 103, while in the armchair direction, a lower peak-to-valley ratio of 5.5 is obtained. Alternatively, a fully spin-polarized photocurrent can also be generated under the illumination of linearly-polarized light by tuning either the photon energy or the polarization angle.
关键词： spin-polarized current,negative differential resistance,InP3 monolayer,quantum transport calculations,Ge doping,spintronic nanodevices
更新于2025-09-23 15:19:57
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The interplay of electron-photon and cavity-environment coupling on the electron transport through a quantum dot system
摘要： We theoretically investigate the characteristics of the electron transport through a two-dimensional a quantum dot system in the xy-plane coupled to a photon cavity and a photon reservoir, the environment. The electron-photon coupling, gγ, and the cavity-reservoir coupling, κ, are tuned to study the system in the weak, gγ ≤ κ, and the strong coupling regime, gγ > κ. An enhancement of current is both seen with increasing gγ and κ in the weak coupling regime for both x- and y-polarization of the photon field. This is a direct consequence of the Purcell effect. The current enhancement is due to the contribution of the photon replica states to the electron transport in which intraband transitions play an important role. The properties of the electron transport are drastically changed in the strong coupling regime with an x-polarized photon field in which the current is suppressed with increasing gγ, but it is still increasing with κ. This behavior of the current is related to the population of purely electronic states and depopulation of photon replica states.
关键词： Quantum master equation,Quantum Dot,Cavity-Quantum electrodynamics,Quantum transport,Purcell effect
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing LLC SPECIAL TOPICS ON TRANSPORT THEORY: ELECTRONS, WAVES, AND DIFFUSION IN CONFINED SYSTEMS: V Leopoldo García-Colín Mexican Meeting on Mathematical and Experimental Physics - México City, México (9–13 September 2013)] - Wave transport in disordered waveguides: Closed channel contributions and the coherent and diffuse fields
摘要： We study the wave transport through a disordered system inside a waveguide. The expectation value of the complex re?ection and transmission coef?cients (the coherent ?elds) as well as the transmittance and re?ectance are obtained numerically. The numerical results show that the averages of the coherent ?elds are only relevant for direct processes, while the transmittance and re?ectance are mainly dominated by the diffuse intensities, which come from the statistical ?uctuations of the ?elds.
关键词： Quantum transport,Disordered waveguides,Random processes
更新于2025-09-16 10:30:52
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Simulation of quantum transport in doped carbon nanotube diode controlled by transverse electric field
摘要： Using first-principle and semi-empirical methods, optical responses and transport characteristics of hybrid CNT-based diodes are studied. The junction is realized by a combination of doping of one half of a nanotube and applying a transverse electric field to the other. Calculations are carried out in the framework of the density functional theory and the nonequilibrium Green function method. The possibility of using these rectifiers in optical nanoantennas is discussed.
关键词： density functional theory,nonequilibrium Green function method,transverse electric field,doped carbon nanotube diode,quantum transport,optical nanoantennas
更新于2025-09-16 10:30:52
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Efficient method for transport simulations in quantum cascade lasers
摘要： An efficient method for simulating quantum transport in quantum cascade lasers is presented. The calculations are performed within a simple approximation inspired by Büttiker probes and based on a finite model for semiconductor superlattices. The formalism of non-equilibrium Green's functions is applied to determine the selected transport parameters in a typical structure of a terahertz laser. Results were compared with those obtained for a infinite model as well as other methods described in literature.
关键词： Büttiker probes,quantum cascade lasers,non-equilibrium Green's functions,quantum transport,semiconductor superlattices
更新于2025-09-11 14:15:04
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[IEEE 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Udine, Italy (2019.9.4-2019.9.6)] 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - ATOMOS: An ATomistic MOdelling Solver for dissipative DFT transport in ultra-scaled HfS <sub/>2</sub> and Black phosphorus MOSFETs
摘要： A state-of-the-art DFT-NEGF based ATOmistic - MOdelling Solver (ATOMOS) was developed and used to assess the physics and fundamental-performance potential of various scaled mono-layer transition-metal-dichalcogenides and black- phosphorus (BP) MOSFETs down to a gate length of 5 nm, including the effect of electron-phonon scattering. Our study highlights the good scalability and drive-current potential of HfS2 and the impact of optical-phonon scattering for BP.
关键词： DFT NEGF,CMOS,2D-material,Semiconductor Physics,Quantum transport
更新于2025-09-11 14:15:04
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Higher-order moments, cumulants, and spectra of continuous quantum noise measurements
摘要： We present general quantum mechanical expressions for higher-order moments, cumulants, and spectra of continuously measured quantum systems with applications in spin noise spectroscopy, quantum transport, and measurement theory in general. Starting from the so-called stochastic master equation of continuous measurement theory, we find that the leading orders of the fluctuating detector output z(t) with respect to the measurement strength β are a white shot noise background, a constant measurement offset, and the leading order quantum noise of the measured operator A. Starting from quantum expressions for the multitime moments (cid:2)z(tn) · · · z(t1)(cid:3) we derive three- and four-time cumulants that are valid in all orders of β covering the full regime between the weak- and strong-measurement limit (Zeno limit). Intriguingly, quantum expressions for the cumulants were found that exhibit the same simple structure as those for the moments after introduction of only a slightly modified system propagator. Very compact expressions for the cumulant-based third- and fourth-order spectra (bispectrum and trispectrum) follow naturally. We illustrate the usefulness of higher-order spectra by treating a real-world two-spin system with strong hyperfine interaction. Moreover, spin noise spectroscopy is shown to have the potential for investigating the transition from weak measurements to the famous quantum Zeno regime for realistic probe laser intensities.
关键词： higher-order moments,stochastic master equation,quantum transport,continuous quantum noise measurements,spin noise spectroscopy,spectra,quantum Zeno effect,cumulants,measurement theory
更新于2025-09-10 09:29:36