Light controlled and probed ferromagnetism of (Cd,Mn)Te quantum wells

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Since the discovery of two-dimensional magnetic materials in 2017, an uncharted territory has opened within the field of spintronics, drawing intense interest from both experimental and computational research. From a computational perspective, studying magnetic materials requires addressing several challenges: achieving accurate simulations of localized electrons, identifying the ground state magnetic ordering, determining the parameters of effective Hamiltonians, such as Hubbard parameters or exchange inte

We demonstrate that the control protocols of quantum information devices can be simulated by assuming a low-rank ansatz for the density matrix. The rationale underlying this assumption is that quantum information protocols, by design, operate in a regime of nearly pure quantum states. Within the low-rank assumption, the simulation of these protocols is considerably faster than solving the full Lindblad master equation. This advantage can be used to increase the accuracy of the simulation by avoiding uncontr

Motivated by the recent observation of a uniform vector chirality (UVC) magnetic order in the maple-leaf lattice (MLL) realization

\mathrm{Ho_3ScO_6}

via powder neutron scattering experiments, we investigate the classical antiferromagnetic Heisenberg model on the maple-leaf lattice. The MLL features three symmetry-inequivalent nearest-neighbor couplings,

J_d

J_t

, and

J_h

. Previous studies, primarily focused on the case where

J_t = J_h

, identified a staggered vector chirality (SVC) order. Extendin

Incorporating 4d and 5d metal ions into coordination frameworks offers a powerful route to quantum materials where orbital delocalization and spin–orbit coupling reshape magnetic and electronic ground states. Yet, such systems remain largely unexplored. We introduce Mo(pyz)2I2, a pyrazine-linked square-lattice material that uniquely couples a paramagnetic heavy transition metal center with ligand-radical character, opening access to spin–orbit-entangled ground states in molecular frameworks. Structural and

In recent years, quantum computers have emerged as a disruptive technology capable of solving problems currently intractable for classical systems. Computation is performed using qubits, which exploit quantum properties like superposition and entanglement, and requires them to operate at cryogenic temperatures. As a result, quantum computers are built around cryostats that reach temperatures as low as \qty{10}{\milli\kelvin}. However, to deliver a significant advantage over conventional approaches, quantum

Understanding the power of quantum data in machine learning is central to many proposed applications of quantum technologies. While access to quantum data can offer exponential advantages for carefully designed learning tasks and often under strong assumptions on the data distribution, it remains an open question whether such advantages persist in less structured settings and under more realistic, naturally occurring distributions. Motivated by these practical concerns, we introduce a systematic framework b

Spin caloritronics refers to research efforts in spintronics when a heat current plays a role. In this review, we start out by reviewing the predictions that can be drawn from the thermodynamics of irreversible processes. This serves as a conceptual framework in which to analyze the interplay of charge, spin and heat transport. This formalism predicts tensorial relations between vectorial quantities such as currents and gradients of chemical potentials or of temperature. Transverse effects such as the Nerns

High-temperature superconductivity emerges on doping holes or electrons into antiferromagnetic copper oxides. The large energy scale of magnetic excitations, for example, compared with phonon energies, is thought to drive superconductivity with high transition temperatures (T c). Comparing high-energy magnetic excitations of hole- and electron-doped superconductors provides an opportunity to test this hypothesis. Here, we use resonant inelastic X-ray scattering at the Cu L 3 -edge to reveal collective excit

We present magnetization and Se-77 Nuclear Magnetic Resonance (NMR) measurements in single crystals of the magnetoelectric compound Cu2OSeO3. The temperature and field dependence of the magnetization suggest a ferrimagnetic ordering at T-c similar or equal to 60 K in a 3up-1down configuration. The easy axis of the magnetization is along the [100] crystallographic direction. The Se-77 NMR line shape data collected at 14.09 T are consistent with the symmetries imposed by the cubic P2(1)3 space group in the te

In a multi-gyrotron system such as the one presently designed for the ITER ECH & ECCD system, stray magnetic fields can significantly alter the operational capabilities of the global system. A numerical study was carried out within the European Gyrotron Consortium (EGYC) to assess the importance of the different effects and their impact on the gyrotron operation. Using the Ariadne++ 3D code, and based on the geometrical layout of the ITER-EC system, the effect of the ITER stray magnetic field combined toget

We report on the temperature dependence of ferroelectric metal-oxide-semiconductor (MOS) transistors and explain the observed improved characteristics based on the dielectric response of ferroelectric materials close to the Curie temperature. The hysteretic current-voltage static characteristics of a fully depleted silicon-on-insulator transistor, with 40 nm vinylidene fluoride trifluorethylene, and 10 nm SiO2 gate stack, are measured from 300 to 400 K. In contrast with conventional MOS field effect transis

We present a spin delocalization effect in radical Si-containing systems, featuring a heteroatom of high electronegativity (such as N, O, or Cl) bonded to the unsaturated Si atom. We find that the higher the electronegativity of the heteroatom, the more the localized spin shifts away from the unsaturated Si atom and the heteroatom toward saturated Si neighbors. We demonstrate that this spin repulsion toward saturated Si atoms is induced by the electronegativity difference between the Si atom and the heteroa

The original magnetic properties of nanometre-sized particles are due to the distinct contributions of volume, surface and step atoms. To disentangle these contributions is an ongoing challenge of materials science. Here we introduce a method enabling the identification. of the remarkably different contributions of surface and perimeter atoms to the magnetic anisotropy energy of two-dimensional nanostructures. Our method uses the generally nonlinear relationship between perimeter length and surface area. At

The orientation dependence of the longitudinal piezoelectric coefficient, d(33)(), is investigated as a function of temperature in BaTiO3 and PbTiO3 crystals using the Landau-Ginsburg-Devonshire theory. We show that a presence of the ferroelectric-ferroelectric phase transitions in BaTiO3 leads to enhanced d(33)() along nonpolar directions. The reason for this is that in the vicinity of a phase transition temperature at which a polarization vector changes its direction (tetragonal-orthorhombic/monoclinic,

Femtosecond luminescence measurements combined with pump-probe experiments using selective excitation of either free carriers or excitons have been performed. The time-resolved luminescence spectra show a striking disparity compared with recently published theoretical models. Large differences in the pump-probe spectra are observed for resonant and non-resonant (continuum) pumping. The origin of these differences is discussed.

We present a systematic study of the oscillator strength of the positively charged excitons (X+) in Cd1-xMnxTe quantum wells. CW-absorption and time-resolved photoluminescence measurements were combined as two approaches for the determination of the oscillator strength. By varying (in a small magnetic field) the spin subband hole distribution at constant total concentration, we observe an increase of the oscillator strength in absorption, proportional to the hole concentration in one spin subband (the one w

We study the coherent optical response of a very high-finesse microcavity with a single quantum well by means of degenerate subpicosecond pump-probe spectroscopy. The dynamics of the ac Stark effect versus Pump intensity is investigated upon tuning the empty-cavity;mode-below and above the exciton transition energy, at the exciton continuum onset. The evolution from a simple dynamical excitonic shift to a dynamical splitting is clearly observed in both eases. The qualitative, agreement with numerical calcul

A dramatic suppression of the absorption of light by exciton polaritons is observed after resonant excitation of the polaritonic modes in a multiple quantum well Bragg structure. Time-resolved reflectivity measurements confirm that this is due to the formation of a dominant superradiant polariton mode created by the light-induced coupling of excitons in different quantum wells that suppress absorption. The stability of the superradiant mode is demonstrated at high excitation powers and at temperatures of up

We report the optical properties of high quality V-groove GaAs/Al0.3Ga0.7.As quantum wires (QWRs) with different thicknesses of the GaAs layer. The systematic investigation of photoluminescence (PL) and photoluminescence excitation (PLE) spectra as a function of the wire size combined with model calculations allows us to study in detail the effect of two-dimensional quantum confinement on valence band mixing and polarization anisotropy. We show that the polarization anisotropy of PL spectra critically depen

Using luminescence upconversion with 100 fs resolution, we have investigated the intersubband scattering of electrons in GaAs quantum wells (QWs). The energy separations between the first and second confined electron subband (E(12)) were more or less than the LO phonon energy (E(LO)) In narrow QWs (E(12) > E(LO)) the intrinsic LO phonon scattering rate is found to be 1.6 x 10(12) s(-1). A Monte Carlo simulation allows us to reproduce the experimental data with high accuracy. In wide QWs (E(12) < E(LO)) We f

Light controlled and probed ferromagnetism of (Cd,Mn)Te quantum wells

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Two-dimensional magnetic materials from first principles

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Interplay of Redox Non-Innocence and Symmetry Breaking in a 4d Coordination Framework

Cryogenic HEMT-based devices and circuits for quantum computing

Information-Theoretic Limits of Quantum Learning via Data Compression

Spin Caloritronics, origin and outlook

Asymmetry of collective excitations in electron- and hole-doped cuprate superconductors

Magnetic properties of the magnetoelectric compound Cu2OSeO3: Magnetization and Se-77 NMR study

Calculation of Stray Magnetic Field Effects on the Operation of the ITER Electron Cyclotron System

Ferroelectric transistors with improved characteristics at high temperature

An electronegativity-induced spin repulsion effect

The remarkable difference between surface and step atoms in the magnetic anisotropy of two-dimensional nanostructures

Piezoelectric anisotropy-phase transition relations in perovskite single crystals

Is luminescence from quantum wells due to excitons?

Oscillator strengths of charged excitons: combining magnetoabsorption and photoluminescence dynamics in semimagnetic quantum wells

Direct observation of an ac Stark splitting in semiconductor microcavities excited above the continuum onset

Suppression of exciton-polariton light absorption in multiple quantum well Bragg structures

Optical spectroscopy study of carriers recombination in quantum wires

Intersubband scattering rates in GaAs quantum wells under selective and resonant excitation, measured by femtosecond luminescence