Materials Today Quantum最新文献

Recent findings regarding spin-orbit torques (SOTs) and current-induced magnetization switching in ferromagnetic (FM) single layers have attracted substantial attention due to the advantage of not necessitating the use of heavy-metal layers. Nevertheless, despite prior studies on the interior structural engineering of the SOT, the external techniques for manipulating the SOT in the FM single layer remains elusive, which is indispensable for the practical application of the single layer SOT devices. Here, we demonstrate external manipulation of SOT generation in CoPd single layer through the fabrication of CoPd film with a composition gradient, utilizing the H₂-absorption property of Pd. It is found that the H-induced strain within the CoPd film plays a pivotal role in generating SOT. Meanwhile, we demonstrate that the critical current density required for the current-induced magnetization switching is markedly diminished with the application of H₂ due to the enhanced SOT generation and reduced perpendicular magnetic anisotropy energy. Our findings offer a straightforward method for external manipulation of single layer SOT devices, and hold the potential for applications of the spintronic devices.

This work used a variational quantum circuit (VQC) in conjunction with a quantitative structure-property relationship (QSPR) model to completely investigate the corrosion inhibition efficiency (CIE) displayed by pyridine-quinoline compounds acting as corrosion inhibitors. Compared to conventional methods like multilayer perceptron neural networks (MLPNN), the VQC model predicts the CIE more accurately. With a coefficient of determination (R²), root mean square error (RMSE), mean absolute error (MAE), and mean absolute deviation (MAD) values of 0.989, 0.027, 0.024, and 0.019, respectively, VQC performs better. The established VQC model predicts the CIE with outstanding predictive accuracy for four newly synthesized pyrimidine derivative compounds: 1-(4-fluorophenyl)- 3-(4-(pyridin-4-ylmethyl)phenyl)urea (P1), 1-phenyl-3-(4-(pyridin-4-ylmethyl)phenyl)urea (P2), 1-(4-methylphenyl)-3-(4-(pyridin-4-ylmethyl)phenyl)urea (P3), and quaternary ammonium salt dimer (P4). It generates remarkably high CIE values of 92.87, 94.05, 94.96, and 96.93 for P1, P2, P3, and P4, respectively. With its ability to streamline the testing and production processes for novel anti-corrosion materials, this innovative approach holds the potential to revolutionize the market.

It is common for the local inversion symmetry to break in crystals, even though the whole crystal has global inversion symmetry. This local inversion symmetry breaking allows for a local Dzyaloshinsky–Moriya interaction (DMI) in magnetic crystals. Here we show that the local DMI can stabilize a skyrmion as a metastable excitation or as a skyrmion crystal in equilibrium. We consider the crystal structure with layered structure as an example, where local inversion is violated in each layer but a global inversion center exists in the middle of the two layers. These skyrmions come in pairs that are related by inversion symmetry. The two skyrmions with opposite helicity in a pair form a bound state. We study the properties of a skyrmion pair in the ferromagnetic background and determine the equilibrium phase diagram, where a robust lattice of skyrmion pairs is stabilized. Our results point to a new direction to search for the skyrmion lattice in centrosymmetric magnets.

Quantum computers allow to solve efficiently certain problems that are intractable for classical computers. For the realization of a quantum computer, a qubit design as the basic building block is a nontrivial starting point. Within a nanoscale ferromagnetic domain wall stabilized by achiral energy, two degenerate chirality forms exist which can be regarded as the two qubit states. Our numerical demonstration shows that the manipulation of spin configurations of the ferromagnetic domain walls is governed by magnetic and electric fields for single-qubit quantum gates, while the Ising exchange coupling facilitates the two-qubit gates. The incorporation of these quantum gates permits universal quantum computation. Furthermore, we discuss the estimation of the coherence time, as well as the initialization and readout of the qubits. Our findings show a practical implementation of quantum computing architectures based on the domain-wall qubits in ferromagnetic materials.

Advent of high mobility perovskite oxide semiconductor BaSnO₃ (BSO) has enabled all-perovskite oxide heterostructures such as 2DEGs and FETs. To date all-perovskite oxide device demonstrations have been focused on finding and integrating the compatible perovskite dielectric oxides such as polar LaInO₃ and LaScO₃ and non-polar BaHfO₃ and SrHfO₃. For these demonstrations the length scale of BSO-based heterostructure devices has been about 100 µm, primarily due to the use of stencil masks for patterning. In order to further reduce the length scale, we employed a top-down approach using both photolithography and chemical etching techniques to pattern FETs made entirely of perovskite oxide materials: Ba_0.997La_0.003SnO₃ channel layer, degenerately doped Ba_0.96La_0.04SnO₃ contact layer, and SrHfO₃ gate oxide layer. FETs of 3 µm channel length were fabricated using hydrofluoric acid and aqua regia as etchants. The FET exhibits a mobility of 38.8 cm²/Vs, an on/off ratio of 5.06 × 10⁷, and a drain current density of 6.05 × 10⁻² mA/μm, consistent with our expectation. These findings demonstrate the feasibility of patterning BSO through photolithography and chemical etching while maintaining the subsequent epitaxial growth, suggesting that BSO can be employed in a broader range of applications as well as for more precise studies of its intrinsic properties.

The linear combination of atomic orbitals (LCAO) is a standard method for studying solids and molecules, it is also known as the tight-binding (TB) method. In most of the implementations only the basis set and the coupling constants are provided, without the explicit definition of kinetic and potential energy operators. The tight-binding scheme is, nonetheless, capable of providing an accurate description of properties such as the electronic bands and elastic constants for many materials. However, for some applications, the knowledge of the underlying electronic potential associated with the tight-binding hamiltonian might be important to guarantee that the actual physics is preserved by the semiempirical scheme. In this work the electronic potentials that arise from the use of tight-binding effective hamiltonians it is explored. The formalism is applied to the extended Hückel tight-binding (EHTB) hamiltonian, which is a two-center Slater$-$Koster approach that makes explicit use of the overlap matrix.