Abstract Mathematical analysis on the existence of eigenvalues is essential because it deeply related to localization, which an exceptionally crucial property quantum walks (QWs). We construct method for eigenvalue problem via transfer matrix space-inhomogeneous three-state QWs in one dimension with a self-loop, extension technique previous study (Kiumi and Saito 2021 Quantum Inf. Process. 20 1...

A critical issue in GaN-based high power light-emitting diodes (LEDs) is how to suppress the efficiency droop problem occurred at high current injection while improving overall quantum efficiency, especially in conventional c-plane InGaN/GaN quantum well (QW), without using complicated bandgap engineering or unconventional materials and structures. Although increasing thickness of each QW may d...

The potential to extend the emission wavelength of photonic devices further into the near- and mid-infrared via pseudomorphic growth on conventional GaAs substrates is appealing for a number of communications and sensing applications. We present a new class of GaAs-based quantum well (QW) heterostructure that exploits the unusual impact of Bi and N on the GaAs band structure to produce type-II ...

Cross-sectional scanning tunneling microscopy (STM) is used to study lattice matched InGaAs/InP quantum well (QW) intermixing induced by ion implantation and thermal annealing. Different strain development in QWs (determined by STM topography of elastic relaxation in cross-sectionally cleaved samples) is found to be dependent upon the range of the implanted ions relative to the QWs. It is found...

Very recently Patel et al. [1] constructed a quantum walk (QW) on a line without using a coin toss instruction, and analyzed the asymptotic behavior of the walk on the line and its escape probability with an absorbing wall. In fact the QW investigated by them can be considered as a class of quantum cellular automata on the line (see [2, 3, 4], for examples), so we call their non-coined QW a qua...

Compared with conventional InGaN Quantum Wells (QWs), staggered QWs offer improved optical and electronic properties. This work studied the carrier concentration, band structure, overlap of hole electron wave functions, polarization field three-layer in blue spectral region analyzed them detail theoretically to explore source dominant mechanism for improvement. Although theoretical studies indi...

High-efficiency InGaN-based yellow light-emitting diodes (LEDs) with high brightness are desirable for future high-resolution displays and lighting products. Here, we demonstrate efficient (∼570 nm) LEDs optimized three-layer staggered quantum wells (QWs) that grown on patterned sapphire substrates. Numerical simulations show the electron–hole wavefunction overlap of InGaN QWs In content exhibi...

In this paper, we present the direct observation of quantum size effects (QSE) on the work function in ultrathin Pb films. By using scanning tunneling microscopy and spectroscopy, we show that the very existence of quantum well states (QWS) in these ultrathin films profoundly affects the measured tunneling decay constant kappa, resulting in a very rich phenomenon of "quantum oscillations" in ka...

We studied optical reflection (OR) and contactless electroreflection (CER) from a periodic system of multiple GaAs/AlGaAs quantum wells (QWs). The system was designed in such way that the electromagnetic resonance of Bragg reflection occurs at the frequency that coincides or is close to the frequency of the exciton-polariton resonance in the wells. Under these conditions there should be electro...