Quantum computers promise to perform computations beyond the reach of modern with profound implications for scientific research. Due remarkable technological advances, small scale devices are now becoming available use. One most apparent applications such a device is study complex many-body quantum systems, where classical unable deal generic exponential complexity states. Even zero-temperature equilibrium phases matter and transitions between them have yet be fully classified, topologically...

The E0 band gap energies and the lattice constants of zinc-blende Zn1−xMgxSe alloys grown by molecular beam epitaxy in composition range 0≤x≤0.95 are determined. A nonlinear dependence on is observed for both band-gap con- stants ternary alloys. To our knowledge this an initial report a bowing constant II–VI alloy. Considering bowings, energy MgSe extrapolated to be about 4.0 eV 5.91 Å, respectively.

We report on a direct observation of free-exciton thermalization in quantum-well structures. A narrow energy distribution free $1s$ excitons is created ZnSe-based quantum wells by emission one LO phonon after optical excitation the continuum states with picosecond laser pulses. The subsequent relaxation dynamics within $1s$-exciton dispersion directly monitored time-resolved studies phonon-assisted photoluminescence. It demonstrated that remains nonthermal for some 100 ps. observed...

Models whose ground states can be written as an exact matrix-product state (MPS) provide valuable insights into phases of matter. While MPS-solvable models are typically studied isolated points in a phase diagram, they belong to connected network models, which we call the MPS skeleton. As case study where completely unearth this skeleton, focus on one-dimensional BDI class---noninteracting spinless fermions with time-reversal symmetry. This class, labeled by topological winding number,...

Out-of-equilibrium phases in many-body systems constitute a new paradigm quantum matter - they exhibit dynamical properties that may otherwise be forbidden by equilibrium thermodynamics. Among these non-equilibrium are periodically driven (Floquet) [1-5], generically difficult to simulate classically due their high entanglement. Using an array of superconducting qubits, we realize Floquet topologically ordered state theoretically proposed Ref. [6], image the characteristic dynamics its...

We report on the binding energy and dephasing of localized biexciton states in narrow ZnSe multiple quantum wells. The measured binding-energy distribution biexcitons shows a width 2.2 meV centered at 8.5 meV, is fairly independent exciton localization energy. In four-wave mixing, photon echo decays fast nonexponentially. This behavior results from inhomogeneous broadening energy, as we show by comparison with an analytical model calculation. decay thus not related to microscopic dephasing.

Quantum dots and quantum wires based on CdZnSe/ZnSe single well heterostructures have been achieved using electron beam lithography wet chemical etching. Photoluminescence spectra of the dot wire structures show a blue shift due to lateral quantization for dimensions below 40 nm. For ground state, confinement energy 16 meV is obtained 28 nm diameter structures. with widths order 20 nm, energies about 5 are observed. The width dependence emission can be described square potential measured sizes

First order distributed feedback laser with periods down to 94 nm based on ZnSe have been realized by electron beam lithography and wet chemical etching. Distributed operation was demonstrated optical excitation using a pulsed N2 laser. A threshold density of 80 kW/cm2 found at room temperature for resonator length 225 μm. From the stop band width, coupling coefficient 120 cm−1 can be estimated. By varying grating period emission wavelength tuned over wide spectral range more than 130 meV....

The potential impact of quantum machine learning algorithms on industrial applications remains an exciting open question. Conventional methods for encoding classical data into computers are not only too costly a advantage in the but also severely limit scale feasible experiments current hardware. Therefore, recent works, despite claiming near-term suitability their algorithms, do provide experimental benchmarking standard datasets. We attempt to solve problem by improving recently proposed...

The dynamics of biexciton formation and the spin-relaxation process excitons in (Zn,Cd)Se/ZnSe quantum wells are investigated systematically using time-resolved photoluminescence spectroscopy. Excitons with well-defined spin orientation were created linearly or circularly polarized light, respectively, while energy exciting laser pulse was tuned to transition ground state heavy-hole exciton. For excitation, rise time luminescence signal directly reflects coefficient. pulses, a strong...

The scaling of the entanglement entropy at a quantum critical point allows us to extract universal properties state, e.g., central charge conformal field theory. With rapid improvement noisy intermediate-scale (NISQ) devices, these computers present themselves as powerful tool study many-body systems. We use finite-depth circuits suitable for NISQ devices variational ansatz represent ground states critical, infinite find relations and verify them numerically two different points, i.e., Ising...

The energy gap of zinc-blende epitaxial layers grown by molecular beam epitaxy has been determined over a wide range composition using optical transmission and reflection an empirical formula for the at room temperature is also given. In addition in situ spectroscopic ellipsometry was used order to determine dependence between growth alloys with compositions x, y as cladding waveguides blue - green light-emitting devices.

Abstract In II–VI material based laser diode structures, the role of excitonic processes for stimulated emission is still rather controversially discussed. this paper, manifestation biexciton recombination in high‐density luminescence ZnCdSe/ZnSe quantum wells investigated by intensity‐ and polarization‐dependent spectroscopy. spite their evidence such spectra, contribution to diodes with moderately confining not confirmed, instead, indication strong Coulomb correlation given when using new...

The refractive index and the E0 energy gap has been determined for a number of Zn1−xMgxSySe1−y alloys with x≤0.3 y≤0.3 at temperatures between 5 300 K. It shown that can be empirically expressed as function gap. Furthermore we have temperature dependence hence these alloys.

We have developed a versatile and low-damage technology to realize quantum dots wires based on CdxZn1−xSe/ZnSe heterostructures. Electron beam lithography was used for pattern definition. The transfer into the semiconductor performed by wet etch process K2Cr2O7:HBr:H2O solution. Preferential etching along crystallographic planes leads well-defined sidewalls of freestanding dot wire structures. Dot sizes down 28 nm 13 been achieved. High photoluminescence efficiencies, even in narrowest...

A systematic experimental and theoretical analysis of the lateral size composition dependence strain release quantization in etched ${\mathrm{Cd}}_{x}{\mathrm{Zn}}_{1\ensuremath{-}x}\mathrm{S}\mathrm{e}/\mathrm{Z}\mathrm{n}\mathrm{S}\mathrm{e}$ quantum wires is presented. Wires with structure sizes down to 14 nm were realized by electron beam lithography wet chemical etching characterized photoluminescence (PL) Raman spectroscopy. For wide (${L}_{x}>40 \mathrm{nm}$), relaxation results a...

Stacking-fault pairs in ZnSe/ZnMgSSe quantum-well structures are found to induce enhanced radiative recombination visible as of bright spots microphotoluminescence intensity maps. Structural investigation by atomic-force microscopy and transmission electron (plan view well cross section) reveal that a widening bending quantum wells occurs when they intersected Frank-type stacking faults. The enlargement the width up 12 bilayers evokes an efficient localization excitons. localizing potential...

The dimensionality dependence of the biexciton formation process is investigated by comparing (Cd,Zn)Se/ ZnSe quantum-dot and quantum-well structures using time-resolved photoluminescence (PL) spectroscopy. Modeling onset PL signal with a system rate equations, we obtain coefficient about $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}{\mathrm{cm}}^{2}/\mathrm{p}\mathrm{s}$ for 35-nm quantum dots...

Abstract Although lasing is meanwhile achieved in various ZnSe‐based heterostructures, the underlying mechanisms are still seriously under debate. The gain spectra of MBE‐grown samples measured using variable‐stripe‐length method. A description for low particle densities possible terms model Ding et al. responsible mechanism assumed to be an induced recombination strongly exchange‐interacting localized excitons, which, however, may a questionable precondition. By means time‐dependent...

Abstract By electron beam lithography and a subsequent wet/dry etch process, optically active nanostructures are developed based on ZnSe with lateral extensions down to 35 nm. Dry etching using Ar + ions is found generate very smooth surfaces, while the photoluminescence efficiency of narrow wires much higher in wet chemically etched structures. As first application deep nanostructures, index coupled distributed feedback laser structures second order realized periods 185 nm base (Cd,...

Spin-flip Raman scattering spectroscopy has been applied to the study of wide band-gap semiconductor materials ${\mathrm{ZnS}}_{x}{\mathrm{Se}}_{1\ensuremath{-}x}$ and ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mg}}_{x}\mathrm{Se}$ in order determine dependence on composition, x, gyromagnetic ratio electrons ${\ensuremath{\Gamma}}_{6}$ conduction band and, thereby, obtain a better understanding parameters underlying structure these materials. The measured values are discussed terms...

In this work we report on the in situ investigation of MBE grown ZnSe surfaces performed simultaneously by reflectance anisotropy spectroscopy (RAS) and reflection high-energy electron diffraction (RHEED). Reconstructions anisotropic ZnSe(001) surface are studied temperature range from 50 °C to 380 °C. With increasing evolves a Se-rich c(2×2)Se via (2×1) Zn-rich c(2×2)Zn reconstruction with transition temperatures depending whether is Se stabilized or not. Each as verified RHEED accompanied...

We performed a pump-and-probe photoluminescence excitation spectroscopy of the stimulated emission ${\mathrm{Zn}}_{0.7}$${\mathrm{Cd}}_{0.3}$Se single-quantum-well (SQW) struture proven to act as an efficient room-temperature laser diode under current injection. Excitonic absorption features in spectra are completely bleached if sample is simultaneously pumped by second fixed wavelength and intensity only 40 kW/${\mathrm{cm}}^{2}$. The stability excitons lasing conditions, thus, seriously...

First order gain and index coupled distributed feedback (DFB) gratings were realized in ZnSe-based laser structures using direct implantation with a focused ion beam for gain-modulated conventional electron lithography modulation. With both technologies, periods below 90 nm could be achieved, permitting DFB emission the blue spectral range. Fine tuning of wavelength steps 0.14 is demonstrated by sampled based on periodic modulation resonator period.