Efficient thermal management under fluctuating ambient conditions is crucial, yet most thermal metamaterials exhibit only positive feedback, causing object temperatures to follow environmental variations and limiting adaptive control. Here, we propose a thermal inverter based on a negative-thermal-coupling mechanism, which realizes counteraction of ambient-temperature fluctuations by inducing an inverse correlation between its central temperature and the environment. Both simulations and experiments confirm this counteractive inverse thermal response. Furthermore, we realize an inverse-temperature cloak that maintains an undisturbed background while exhibiting negative thermal coupling at its core. By harnessing negative thermal coupling and inverse-temperature regulation, our work establishes a paradigm for advanced thermal-management technologies.

Transition-metal dichalcogenides (TMDs) are a novel class of quantum materials with significant potential in spintronics, optoelectronics, valleytronics, and optovalleytronics. TMDs exhibit strong spin-orbit coupling, enabling efficient spin-charge interconversion, which makes them ideal candidates for spin-orbit torque-driven spintronic devices. In this study, we have investigated the spin-to-charge conversion through ferromagnetic resonance in $\mathrm{Mo}\mathrm{S}$${}_2$/$\mathrm{Cu}$/$\mathrm{Co}$-$\mathrm{Fe}$-$\mathrm{B}$ heterostructures with varying $\mathrm{Cu}$ spacer thicknesses. The conversion efficiency, quantified by the spin Hall angle, has been enhanced by an order of magnitude due to $\mathrm{Cu}$ intercalation. Magneto-optic Kerr effect microscopy has confirmed that $\mathrm{Cu}$ does not significantly modify the magnetic domains, indicating its effectiveness in decoupling $\mathrm{Mo}\mathrm{S}$${}_2$ from $\mathrm{Co}$-$\mathrm{Fe}$-$\mathrm{B}$. This decoupling preserves the spin-orbit coupling (SOC) of $\mathrm{Mo}\mathrm{S}$${}_2$ by mitigating the exchange interaction with $\mathrm{Co}$-$\mathrm{Fe}$-$\mathrm{B}$, as proximity to localized magnetization can alter the electronic structure and the SOC. First-principles calculations have revealed that $\mathrm{Cu}$ intercalation notably enhances the spin Berry curvature and spin Hall conductivity, contributing to the increased spin Hall angle. This study demonstrates that interface engineering of ferromagnet–TMD-based heterostructures can achieve higher spin-to-charge conversion efficiencies, paving the way for advancements in spintronic applications.

Local intensity enhancement by plasmonic nanoparticles is widely used in optics and photonics; however, the effect is usually based on dipole resonances in the particles. Recently, it has been shown that quadrupole and octupole resonances can exhibit comparable or even higher near-field enhancement. In this work, we focus on the near-field enhancement by a metasurface composed of gold-disk dimers arranged in a rectangular array. We find that, owing to an octupole plasmon resonance coupled to a surface lattice resonance, exceptionally high near-field enhancement in the dimer gaps can be achieved in the visible spectral range. To gain insight into the effect, we develop an analytical model for the effective dipole and octupole polarizabilities of the particles in an array, and discover that at decreasing array periods, the dipole polarizability tends to vanish, while the octupole polarizability rapidly increases. Hence, octupole resonances can find applications in high-density arrays of plasmonic resonators. We propose a method to numerically evaluate multipole polarizabilities of a single particle, applying it to the gold dimer that we consider. The influence of the array on the effective polarizabilities is then verified by numerical calculations, and good agreement is obtained. Our results may open new avenues for investigating the properties of periodic plasmonic structures based on higher-order multipole resonances and their applications.

The acoustic vortex beam carrying orbital angular momentum (OAM) provides a new degree of freedom for sound manipulation, with promising applications in diverse fields ranging from acoustic communication to particle manipulation. However, their propagation in free space is subject to the severe divergence effect, resulting in limited operating distance and reduced signal intensity. Here, we propose a mechanism for generating a divergence-suppressed acoustic vortex beam through subwavelength dipole metamaterials in a broadband, flexible, and compact way. We theoretically reveal that the enhanced directivity of the man-made dipole can effectively reduce the high-spatial-frequency wave-vector component of the generated vortex beam in the radial direction and thereby suppress the beam’s divergence. As a practical implementation, a blocklike acoustic metamaterial is systematically designed for converting the monopole emission into a dipole in a broad bandwidth, whose acoustic properties are also analytically deduced. The effectiveness of a dipole metamaterial-empowered phased array is demonstrated both numerically and experimentally, showcasing that the divergence angle and the main lobe width of a particular first-order vortex beam are reduced by 45% and 23% on average, respectively, within the range of 1000–1600 Hz. Thanks to the compatibility with the phased array, both the topological charge and the deflection angle of the emitted vortex beam can be flexibly modulated without altering metamaterials. We anticipate that our proposed mechanism will promote the application of acoustic vortex beams in various fields, such as long-distance OAM communication and beyond.

Nuclear magnetic resonance gyroscopes (NMRGs) detect the noble gas nuclear spin precession using an in situ parametric modulation Rb atomic magnetometer. However, conventional phase-sensitive demodulation (PSD) suffers from a degraded signal-to-noise ratio in detecting the nuclear spin precession signal due to interference from oscillating magnetic fields. This work demonstrates a single-axis phase-insensitive demodulation (PISD) magnetometer as a novel signal processing configuration for NMRGs. We detail the magnetometer construction and optimize its control parameters, achieving a sensitivity of 100 fT/${\mathrm{Hz}}^{1/2}$. Crucially, the PISD magnetometer significantly outperforms the traditional NMRG dual-axis PSD magnetometer in suppressing crosstalk from unwanted oscillating magnetic fields along orthogonal axes (x or y), reducing the crosstalk ratio of oscillating magnetic fields to 0.05%, nearly an order of magnitude improvement. To evaluate the effectiveness of this scheme in detecting nuclear spin precession signals under realistic interference conditions, the nuclear spin precession signals including crosstalk from the oscillating magnetic fields are measured under low pump-power conditions.

Accurate temperature measurement at the nanoscale is crucial for thermal management in next-generation microelectronic devices. Existing optical and scanning-probe thermometry techniques face limitations in spatial resolution, accuracy, or invasiveness. In this work, we demonstrate a fast and noncontact nanothermometry method based on temperature-induced changes in electron backscattering diffraction (EBSD) patterns captured by a high-performance direct electron detector within a scanning electron microscope (SEM). Using dynamical electron simulations, we establish the theoretical temperature sensitivity limits for several semiconductors ($\mathrm{Si}$, $\mathrm{Ge}$, $\mathrm{Ga}\mathrm{As}$, and $\mathrm{Ga}\mathrm{N}$), showing that thermal diffuse scattering leads to a measurable smearing of Kikuchi bands in the EBSD patterns. We develop a Fourier analysis method that captures these subtle changes across the full diffraction pattern, achieving a simulated temperature sensitivity of approximately 0.15% per K. Experimental results on silicon confirm a sensitivity of 0.14% per K and achieve a 13-K temperature uncertainty with a 10-s acquisition time, and enable spatial temperature measurement under thermal gradients. Our approach offers a pathway toward practical and high-resolution thermal measurement directly in SEMs, expanding the toolbox for device-level thermal diagnostics.

Accurate modeling of magnetic materials is essential for understanding their fundamental properties and advancing technological applications. The widely used methods based on the magnetic force theorem often fall short due to neglecting effects from longitudinal spin fluctuations and struggling with predicting the high-temperature behavior of itinerant magnets, as demonstrated by the significant underestimation of the Curie temperature of nickel. In this work, we demonstrate accurate simulation of magnetic materials by combining high-throughput first-principles calculations with a comprehensive model spin Hamiltonian to predict magnetic phase transitions. The Hamiltonian explicitly includes long-range exchange interactions, longitudinal fluctuations, magnetic anisotropy, and biquadratic interactions. By using a moderately sized data set for parametrization, we achieve an optimal balance between accuracy and efficiency. We validate the method by successfully calculating the Curie temperature of strongly itinerant nickel, which closely matches experimental values and outperforms previous theoretical predictions. Additionally, we apply the method to $\mathrm{Fe}$, $\mathrm{Co}$, and $\mathrm{Cr}\mathrm{Te}$${}_2$, further demonstrating its reliability. This method provides a valuable tool for discovering and designing new magnetic materials, hopefully offering crucial insights that accelerate material innovation and device development.

Future quantum information processors require tunable coupling architectures that can produce high-fidelity logical gates between two or more qubits. Parametric coupling is a powerful technique for generating tunable interactions between many qubits. Here, we present a highly flexible parametric coupling scheme with superconducting qubits that provides complete removal of residual $ZZ$ coupling and the implementation of driven SWAP or SWAP-free controlled-$Z$ ($CZ$) gates. Our fully integrated two-dimensional on-chip coupler design is only weakly flux tunable, cancels static linear coupling between the qubits, avoids internal coupler dynamics or excitations, and is extensible to multiqubit circuit-QED systems. Exploring gate fidelity versus gate duration allows us to maximize two-qubit gate fidelity, while providing insights into possible error sources for these gates. Randomized benchmarking over several hours reveals that the parametric SWAP $CZ$ gate achieves an average fidelity of $99.44\pm 0.09\mathrm{\%}$ in a gate duration of 70 ns and that a dispersively driven parametric SWAP-free $CZ$ gate attains an average fidelity of $99.47\pm 0.07\mathrm{\%}$ in only 30 ns. The fidelity remained above this value for over 8 h and peaked twice with a maximum of $99.67\pm 0.14\mathrm{\%}$. Overall, our parametric approach combines versatility, precision, speed, and high performance in one compact coupler design.

Quantum-well (QW)-based light emitters, such as light-emitting diodes (LEDs) and lasers, of various semiconductor materials experience a reduction in their efficiency when operating at higher temperatures, a phenomenon referred to as “thermal droop.” Among the various claims on the origins of thermal droop, an increased overflow current with increasing temperatures is a common contender. Since overflow of carriers can only occur when the junction voltage $V_{\mathrm{Junction}}$ approaches the built-in voltage $V_{\mathrm{BI}}$ of any diodes, we develop a simple method relating the difference between $V_{\mathrm{Junction}}$ and $V_{\mathrm{BI}}$ to approximate the upper limit of overflow occurring in QW-based light-emitting diodes. The measured difference between $V_{\mathrm{Junction}}$ and $V_{\mathrm{BI}}$ of state-of-the-art commercial blue and green $\mathrm{In}\mathrm{Ga}\mathrm{N}$-based LEDs at temperatures up to ∼450 K suggests negligible overflow. To further experimentally verify the absence of overflow, we perform temperature-dependent electron emission spectroscopy on the same commercial blue and green LEDs and find no evidence of thermally enhanced overflow carriers up to ∼450 K. In agreement with our claims that $V_{\mathrm{Junction}}$ must approach $V_{\mathrm{BI}}$ for overflow to occur, two-dimensional temperature-dependent electrical simulations of violet, blue, and green LEDs including alloy disorder and V-defects demonstrate that overflow can be significant in violet LEDs, where the small band offset between the $\mathrm{In}\mathrm{Ga}\mathrm{N}$ QW and $\mathrm{Ga}\mathrm{N}$ cladding layers due to the larger QW bandgap requires larger $V_{\mathrm{Junction}}$ to reach standard operating current densities, thereby approaching $V_{\mathrm{BI}}$. By contrast, simulations indicate that overflow is negligible in blue and green LEDs, whose smaller QW bandgaps result in smaller quasi-Fermi levels difference to reach significant carrier injection, resulting in a $V_{\mathrm{Junction}}$ much smaller than $V_{\mathrm{BI}}$ up to large operating current densities. Considering that overflow is negligible in blue and longer-wavelength LEDs, and our observations of the large thermal droop occurring at low current densities, where Shockley-Read-Hall (SRH) recombination dominates, we conclude that thermally enhanced SRH processes are the most significant contributor to thermal droop. Finally, we also simulate the carrier densities in the different QWs of a multiple-QW LED and observe a reduction in the total carrier density at a given operating current density, which results in a decrease in the total Auger-Meitner current of the LED from just the thermally enhanced carrier redistribution among QWs without taking any possible additional temperature dependence of their recombination coefficients. Taking all this into account, minimizing thermal droop effects in LEDs can be achieved by a reduction in defect density, using wider band gap p-n junction-defining cladding layers, and operating at higher currents.

Acoustically driven ferromagnetic resonance (FMR) in magnetostrictive-piezoelectric thin-film heterostructures holds significant potential for detecting weak biomagnetic signals from human physiological activity. Minimizing the FMR linewidth is crucial for such applications. This study explores FMR linewidth reduction by examining the properties of alternately sputtered multilayered magnetostrictive $(\mathrm{Fe}\mathrm{Ga}/\mathrm{B}{)}_n$ thin films on piezoelectric ${\mathrm{Li}\mathrm{Nb}\mathrm{O}}_3$ substrates, all with 20 nm thicknesses. As the number of repeating layers (n) increases from 4 to 20, the damping constant declines sharply for n = 4–8, followed by a much slower decrease for n = 8–20. In contrast, inhomogeneity line broadening exhibits a U-shaped trend. These effects collectively yield minimal FMR linewidths at n = 12 and n = 16, demonstrating that optimizing n can effectively reduce the FMR linewidth. Notably, the lowest linewidths observed are smaller than those of a cosputtered $\mathrm{Fe}\mathrm{Ga}\mathrm{B}$ film with the same composition and thickness on an identical ${\mathrm{Li}\mathrm{Nb}\mathrm{O}}_3$ substrate. This suggests that the multilayered approach outperforms the conventional cosputtering approach for producing low-linewidth magnetic thin films, offering insights into acoustically driven FMR-based high-sensitivity magnetic field sensing devices.

In chiral magnets, the magnetic textures surrounding domain walls exhibit a rich variety of structures, offering insights into fundamental physics and potential applications in spintronic devices. Conical spirals and related structures possess intrinsic in-plane directionalities governed by the phase factor ${\varphi }_0$, which are often obscured in long spirals, owing to cylindrical symmetry, but become prominent in short spirals or thin films. Using micromagnetic simulations, we systematically studied magnetic textures at ferromagnetic conical interfaces (FCIs), including one-dimensional (1D) and two-dimensional (2D) FCIs with various shapes. Surface spirals (SSs) emerge adjacent to these FCIs, closely linked to the cone’s in-plane reorientation. In 1D FCIs, reorientation controls the presence, shape, and topological charge of the SS, with a discontinuity point observed where spirals with opposite charges form on opposite sides. In 2D FCIs, eyebrowlike SSs are evident. The reorientation angle between top and bottom SSs is controlled by the film thickness, similar to stacked spirals reported previously. We further demonstrate that SSs form at the facets of skyrmion clusters within the conical phase, as confirmed by both simulations and Lorentz transmission electron microscopy in thin ${\mathrm{Co}}_8{\mathrm{Zn}}_{10}{\mathrm{Mn}}_2$ films. The experiments specifically reveal two distinct formation pathways: thermally activated cogrowth and field-driven transformation from residual helices. These findings establish ${\varphi }_0$ as a fundamental control parameter for magnetic states, enabling promising spintronic functionalities, such as multistate memory through SS polymorphism and energy-efficient neuromorphic computing via controlled topological transitions.

We propose a digitally controlled conveyor-belt shuttling method for silicon-based quantum processors, addressing the scalability challenges of conventional analog sinusoidal implementations. By placing a switch matrix and low-pass filters in a cryogenic environment, our approach synthesizes near-sinusoidal waveforms from a limited number of dc voltage levels. Simulation results demonstrate that the proposed method achieves fidelity comparable to analog methods while significantly reducing wiring overhead and power dissipation. Moreover, the design offers robustness against device-level variations, enabling large-scale integration of high-fidelity spin shuttling for quantum error correction.

Broadband quantum-limited parametric amplifiers (PAs) are essential components in quantum information science and technology. Impedance-engineered resonator-based PAs and traveling-wave PAs are the primary approaches taken to overcome the gain-bandwidth constraint. While the former PAs are simpler to fabricate, the target characteristic impedance $Z_{\mathrm{NR}}$ of the nonlinear resonator has been restricted to be below $10\mathrm{\Omega }$, requiring large capacitance. Moreover, these PAs have only been implemented with aluminum-based Josephson junctions (JJs), hindering their operation at high temperatures or strong magnetic fields. To address these issues, we propose a three-stage impedance-transformer scheme, showcased with a 20 nm thick, 250 nm wide, high-kinetic-inductance niobium-titanium-nitride ($\mathrm{Nb}\mathrm{Ti}\mathrm{N}$) film. Our scheme enables $Z_{\mathrm{NR}}$ up to several tens of ohms—a tenfold improvement over conventional designs, achieved through an additional quarter-wavelength transmission line with a characteristic impedance of 180 $\mathrm{\Omega }$. Our kinetic-inductance impedance-engineered parametric amplifiers (KIMPAs), featuring a 330 fF shunt capacitor, demonstrate a phase-preserving amplification with a 450-MHz bandwidth at 17 dB gain, and added noise ranging from 0.5 to 1.3 quanta near the center frequency of 8.4 GHz. Owing to the high critical current of the $\mathrm{Nb}\mathrm{Ti}\mathrm{N}$ nanowire, the KIMPA also achieves an output saturation power of up to $-51\pm 3$ dBm, approximately 25 dB higher than that of JJ-based PAs. This scheme also opens new possibilities for other three-wave-mixing building blocks.

Sub-Doppler laser spectroscopy is crucial for laser-frequency stabilization, playing a significant role in atomic physics and precision measurement. However, despite decades of development, inefficient atomic utilization remains a widespread issue. Most existing methods rely on single-frequency lasers, and due to the Doppler effect, only a small fraction ($<1\mathrm{\%}$) of atoms with near-zero longitudinal velocities are utilized, severely limiting improvements in the spectral signal-to-noise ratio ($S/N$). Here, we propose a velocity-comb modulation transfer spectroscopy (VC-MTS) solution that leverages the velocity-selective resonance of modulated $N$-frequency lasers, seeming as an optical comb, to enhance the utilization of nonzero-velocity atoms, which optimizes the spectral amplitude and frequency instability by $N$ and $\sqrt{N}$ times, respectively. Unlike traditional MTS, in this work, each pair of counterpropagating lasers interacts with atoms from different longitudinal velocity groups, independently contributing to the amplitude and $S/N$. Preliminary proof-of-principle results show that the frequency stability of the triple-frequency laser is improved by $\sqrt{3}$ times compared to the single-frequency laser. With more frequency components, VC-MTS stabilized lasers are expected to achieve order-of-magnitude breakthroughs in frequency stability, taking an essential step toward next-generation compact optical clocks. This method also applies to quantum systems with wide velocity distributions, offering an innovative perspective on laser spectroscopy and inspiring further intriguing applications.

We report the experimental measurement of a magic wavelength at 476.823 62(8) nm for the ${}^{88}\mathrm{Sr}5s^2{}^1{\mathrm{S}}_0\to 5s5p{}^3{\mathrm{P}}_0$ clock transition. The magic wavelength is determined through an ac Stark shift spectroscopy of atoms in an optical dipole trap. The value is in reasonable agreement with the theoretical prediction, differing by 0.061(54) nm. This magic wavelength, being shorter than the commonly used one at 813 nm, will be important for applications such as Bragg-pulse matter-wave interferometry involving both clock states. This work also paves the way for quantum simulation with a shorter lattice constant.

The orthorhombic $Pca{2}_1$ phase of ${\mathrm{Hf}\mathrm{O}}_2$ exhibits exceptional ferroelectric stability at the nanoscale, yet its intrinsically high coercive field $E_c$ remains a significant obstacle to practical applications. The recent discovery of an interstitially doped ferroelectric rhombohedral R3m phase in ${\mathrm{Hf}\mathrm{O}}_2$ offers a promising route to reducing $E_c$. However, the atomic-scale mechanisms driving this behavior remain incompletely understood. Here, using phonon analysis combined with density functional theory simulations, we reveal that interstitial doping and compressive strain strengthen the weak trilinear couplings among the phonon modes that condense in the R3m phase and induced additional modes. These enhanced couplings dramatically increase the polarization, enabling switching at a remarkably low $E_c$. Our first-principles simulations show that the polarization response strongly depends on the interstitial dopant, as $\mathrm{Ti}$ induces large polarization under a slight compressive strain, while $\mathrm{Ce}$, $\mathrm{Hf}$, and $\mathrm{Zr}$ require a threshold strain to trigger a polarization jump. Interestingly, we further show that all group-IV interstitial dopants remarkably reduce the $E_c$ under compressive strain. These insights demonstrate that interstitial doping, combined with compressive strain, is a powerful strategy for tuning the ferroelectric properties of ${\mathrm{Hf}\mathrm{O}}_2$ and offers a promising pathway to enhanced polarization and reduced switching barriers in next-generation ferroelectric devices.

The poroelastic properties of tissues regulate molecular transport and mechanical signaling, yet their evolution during aging remains poorly understood. In particular, senescent fibroblasts accumulate in aged tissues, contributing to extracellular matrix (ECM) remodeling, but their impact on tissue mechanics and permeability is unclear. In this study, we develop a microfluidic-based in vitro model to assess the poroelastic properties of collagen gels embedded with senescent fibroblasts over time. Our approach integrates periodic pressure actuation with real-time pressure monitoring in a sealed air cavity, enabling the detection of fluid permeation and solid matrix deformations. We analyze our data using analytical and numerical models based on a porohyperelastic framework that combines the compressible neo-Hookean elasticity with the Kozeny-Carman permeability relationship. We demonstrate that senescent fibroblasts induce a progressive softening of the ECM without altering its permeability. Immunostaining reveals that this softening correlates with structural reorganization of the collagen network characterized by increased branching and network remodeling. Our findings provide insights into the biomechanical effects of senescent fibroblasts on ECM homeostasis. We further argue that our platform offers a unique solution to investigate ECM remodeling not only in aging but also in fibrosis, cancer progression, or regenerative medicine strategies.

The spatially resolved near-field radiative heat transfer between a nanoscale probe and a substrate is studied in the fluctuational electrodynamics framework within the dipolar approximation. It is shown that the introduction of a thin polar film atop a nondispersive substrate can lead to both an enhancement and a lateral focusing of the heat exchange. The influence of the probe-substrate separation, film thickness, and substrate permittivity is analyzed, revealing that the effect originates from near-field interactions governed by the interplay between film-induced modifications of electromagnetic mode dispersion and the distance-dependent coupling strength. The results highlight a viable route toward the active control of local radiative heat transfer at the nanoscale.