Newton

Mixed-dimensional transport and evidence for one-dimensional edge modes in thin-film Bi4Br4 field-effect transistors The quasi-one-dimensional (quasi-1D) material Bi4Br4 is predicted to be a higher order topological insulator (TI), in which both the bulk and the surface states are gapped by 120 meV and 20 mV, respectively, and helical 1D modes at the edges are topologically protected. Zhang et al. reveal the contributions from 3D bulk, 2D surface, and 1D edge conduction channels via transport studies of Bi4Br4 thin films as a function of gate voltage, temperature, and magnetic field.

Online now: Mixed-dimensional transport and evidence for one-dimensional edge modes in thin-film Bi4Br4 field-effect transistors #newton #physics

Pressure-induced metal-insulator and paramagnet-altermagnet transitions in rutile OsO2 single crystals Rutile OsO2, isostructural to RuO2, has been theoretically predicted to host altermagnetism, yet experimental studies remain scarce. Zhao et al. report the successful growth of rutile OsO2 single crystals and show that OsO2 remains paramagnetic at ambient conditions while lying near the paramagnetic-altermagnetic phase boundary. High-pressure electrical transport measurements combined with hybrid functional calculations reveal that pressure enhances the Coulomb interaction U, driving altermagnetic phase evolution together with a metal-insulator transition.

Online now: Pressure-induced metal-insulator and paramagnet-altermagnet transitions in rutile OsO2 single crystals #newton #physics

Hybridization of non-Hermitian topological interface modes One of the oldest topological edge states, the Jackiw-Rebbi (JR) interface mode, is resurging in photonics—now with a radiative, non-Hermitian twist. Wang et al. reveal the hybridization of two JR modes in subwavelength dielectric gratings. The hybridization leads to the formation of bonding/antibonding modes coupling with emitters exhibiting distinct characteristics, which can be tuned by adjusting the separation between the interfaces. This framework paves the way for advanced beam steering and light display applications while providing a foundation for exploring more intricate non-Hermitian physics.

Online now: Hybridization of non-Hermitian topological interface modes #newton #physics

A universal design and benchmarking framework for indoor photovoltaics Indoor photovoltaics (IPVs) can sustainably power the growing smart-device ecosystem, yet they are commonly designed and evaluated using human-vision metrics and arbitrary spectra, impairing progress. Khampa et al. propose a universal, spectrum-aware framework for IPV design and benchmarking. By charting realistic indoor lighting diversity, they reveal an expanded optimal band-gap range (1.45–2.1 eV), introduce the spectral onset at 95% cumulative irradiance to unify IPV trends, and implement locus-based benchmarking to capture full efficiency spaces of IPVs, enabling fair cross-device comparisons.

Online now: A universal design and benchmarking framework for indoor photovoltaics #newton #physics

Computation-aided design of color centers for quantum information processing Color centers in semiconductors enable many quantum technologies, yet their properties remain difficult to predict. In this perspective, Li, Gali, and Huang focus on advances in computational methods and workflows for understanding and designing color centers, highlighting key theoretical challenges and emerging strategies toward more predictive, theory-driven discovery.

Online now: Computation-aided design of color centers for quantum information processing #newton #physics

Progress and prospects of magnetic topological materials for spintronic applications Magnetic topological materials are exotic compounds that merge robust topological electronic states with magnetic order. Recent developments include the quantum anomalous Hall effect, low-dissipation edge states, and spintronic applications. However, their low Curie and Néel temperatures limit stability at room temperature. In this review, Chen, Chi, and Moodera revisit the theoretical basis, classify various magnetic topological phases, and discuss their spintronic uses and ongoing challenges, offering a comprehensive overview of the field’s current status and future directions.

Online now: Progress and prospects of magnetic topological materials for spintronic applications #newton #physics

Frozonium: Freezing anharmonicity in Floquet superconducting circuits Superconducting qubits typically have a fixed anharmonicity after fabrication, forcing a trade-off between highly anharmonic devices that are needed for qubit operations and highly harmonic devices that can be useful for quantum memory. Lewellen et al. propose a Floquet-engineered qubit, termed frozonium, that can dynamically access both regimes within a single device. In its harmonic regime, frozonium is robust against external dephasing, highlighting its promise as a platform for quantum memory.

Online now: Frozonium: Freezing anharmonicity in Floquet superconducting circuits #newton #physics

Flexoelectricity-enabled 360° polar locomotion of nematic skyrmions Liquid crystals offer a versatile platform to study solitons. Chen et al. demonstrate that skyrmions confined in a thin chiral nematic layer can be made electrically “directional” through flexoelectricity. By adjusting the voltage amplitude and polarity, their in-plane direction of motion can be steered continuously and their speed tuned. This turns a topological texture from a largely static pattern into a reprogrammable, field-driven quasiparticle and points to a general route for controllable transport of emergent structures in driven soft matter.

Online now: Flexoelectricity-enabled 360° polar locomotion of nematic skyrmions #newton #physics

Phosphonic-acid-reinforced polymer hole transport layers for deployable p-i-n perovskite photovoltaics In perovskite photovoltaics, the interfaces remain a crucial subject for improving performance. Degradation often proceeds from insufficient protection at interfaces. Kong et al. combine commonly used hole transport materials to create a modified hole transport layer that far outperforms the state-of-the-art single layers, improving performance and leading to a demonstration of a relatively long-term operational durability test for perovskite photovoltaics in low Earth orbit.

Online now: Phosphonic-acid-reinforced polymer hole transport layers for deployable p-i-n perovskite photovoltaics #newton #physics

Electron spin resonance scanning tunneling microscopy beyond a single spin Electron spin resonance scanning tunneling microscopy (ESR-STM) combines atomic-resolution imaging with quantum coherent spin control. This review highlights three transformative directions of ESR-STM beyond single-spin manipulation: from single spins to multiple spins for quantum gate operations, from electron spins to nuclear spins for high-fidelity qubits, and from surface-based to tip-based for quantum sensing. Rapid advances along these directions suggest that ESR-STM may soon become a powerful tool for investigating new qubit platforms, nanoscale magnetism, and exotic quantum materials.

Online now: Electron spin resonance scanning tunneling microscopy beyond a single spin #newton #physics

In-sensor computing of sonar data using graphene ionic transistors Sonar uses sound waves to navigate and detect objects underwater, but traditional systems rely on energy-intensive piezoelectric arrays for signal filtering. Varkey et al. highlight the use of 2D materials in graphene-Nafion interfaces for in-sensor computing and its sonar application. Devices are shown to distinguish different frequencies based on the time required to reach a designated threshold, with devices having a low-frequency sonar range while also sensing and distinguishing whale waveforms.

Online now: In-sensor computing of sonar data using graphene ionic transistors #newton #physics

Tunable itinerant ferromagnetism in two-dimensional FePd2Te2 hosting 1D spin chains One-dimensional (1D) magnetism hosts unconventional spin phenomena but is often hindered by poor stability. Ruiz et al. show that the two-dimensional ferromagnet FePd2Te2 naturally embeds robust 1D spin chains with strong in-plane anisotropy. Their first-principles calculations uncover highly anisotropic exchange interactions and tunable chain-length-dependent magnetism while predicting two new family members: CoPd2Te2 (a ferromagnet) and NiPd2Te2. The resulting anisotropic magnon dispersion enables unidirectional spin-wave propagation, highlighting two-dimensional lattices as stable hosts for stabilizing and controlling 1D magnetism.

Online now: Tunable itinerant ferromagnetism in two-dimensional FePd2Te2 hosting 1D spin chains #newton #physics

Unraveling scattering contributions to the nonlinear Hall effect in topological insulator Bi2Te3 The nonlinear Hall effect (NLHE) enables efficient, ultrafast AC-DC rectification without threshold voltages, promising compact energy-harvesting and wireless technologies. Wang et al. reveal that temperature-dependent NLHE in high-quality Bi2Te3 is governed by three skew-scattering channels: impurity, phonon, and hybridized contributions. Impurity scattering dominates at low temperatures, while phonon scattering prevails near room temperature. The competition between these mechanisms leads to a sign inversion around 230 K. This quantitative understanding of competing scattering mechanisms provides design principles for high-performance NLHE-based devices.

Online now: Unraveling scattering contributions to the nonlinear Hall effect in topological insulator Bi2Te3 #newton #physics

Domain-wall-driven anomaly in hydrodynamic phonon transport in SrTiO3 Pronounced size effects in hydrodynamic phonon transport are typically confined to the micrometer scale. Guo et al. show that, in SrTiO3, ferroelastic domain walls generate an anomalous millimeter-scale size dependence. By narrowing the sample width, they reveal that increased domain wall density progressively suppresses phonon Poiseuille flow, identifying domain wall engineering as a powerful strategy for tailoring hydrodynamic heat transport at cryogenic temperatures.

Online now: Domain-wall-driven anomaly in hydrodynamic phonon transport in SrTiO3 #newton #physics

Spin-charge correlations at the pseudogap Understanding the mechanisms behind correlated quantum states such as those in cuprate superconductors remains challenging. Writing in Proceedings of the National Academy of Sciences, Chalopin et al. use an ultracold atoms quantum simulator to reveal spin-charge correlations with a temperature scale comparable to the pseudogap temperature.

Online now: Spin-charge correlations at the pseudogap #newton #physics

Colloidal Magnus effect in polymer solutions Toward elucidating the microscopic origin of the Magnus effect, De Corato et al. theoretically identify and validate polymer transport induced by stress gradient, which causes unexpected sideways drifts of colloids in complex fluids. This understanding facilitates the prediction of colloidal motion and guides the design of microscale devices operating in complex fluid environments. Achieving parameter-free agreement with recent experiments confirms the physical insights underlying the theory.

Online now: Colloidal Magnus effect in polymer solutions #newton #physics

Exact universal characterization of chiral-symmetric higher-order topological phases Higher-order topological phases feature boundary states at corners or hinges of a material, extending beyond traditional surface or edge modes. The correspondence between invariants and these boundary states often relies on heuristic assumptions. Li et al. establish a rigorous correspondence between Bott index vectors and zero-energy corner states, using position operator polynomials to capture intricate patterns in arbitrary geometries and resolve long-standing inconsistencies in the field.

Online now: Exact universal characterization of chiral-symmetric higher-order topological phases #newton #physics

Salt-mediated bidirectional propulsion of oil droplets in confined spaces Solute gradients can initiate oil droplet transport through diffusiophoresis and solutal Marangoni effect. Duong et al. report that surfactant-laden droplets undergoing diffusiophoretic migration in extreme salinity can rapidly demulsify and reverse their motion, revealing an antagonistic interaction between the two mechanisms.

Online now: Salt-mediated bidirectional propulsion of oil droplets in confined spaces #newton #physics

Cartesian nodal lines and magnetic Kramers Weyl nodes in spin-split antiferromagnets Do unique forms of topological band degeneracy exist within the band structure of spin-split antiferromagnets? This is a fundamental question that has garnered recent interest in the condensed matter community. Zhuang et al. explore this question theoretically and identify two such degeneracies—Cartesian nodal lines and magnetic Kramers Weyl nodes—that give rise to a range of exotic properties and intriguing phenomena, including topological boundary states with unconventional spin textures, enhanced-quantized circular photogalvanic effects, and large anomalous Hall effects.

Online now: Cartesian nodal lines and magnetic Kramers Weyl nodes in spin-split antiferromagnets #newton #physics

Dimensional band engineering in asymmetrical van der Waals heterostructures Transition metal dichalcogenides (TMDs) exhibit diverse quantum phases, including magnetism, superconductivity, and topological order. Their layered structure allows isolation and stacking of atomically thin flakes to engineer artificial crystals with tailored properties. Clark et al. demonstrate that simply stacking two distinct few-layer TMD flakes creates heterostructures with fully coherent electronic bands across lattice-mismatched interfaces. These asymmetric stacks emulate ordered crystals’ out-of-plane electronic behavior, enabling bulk band phenomena such as kz-driven topological band inversions.

Online now: Dimensional band engineering in asymmetrical van der Waals heterostructures #newton #physics

Spin-valley locking and pure spin-triplet superconductivity in noncollinear antiferromagnets proximitized to conventional superconductors Spin-triplet superconductivity is crucial for superconducting spintronics and topological quantum computation but remains challenging to realize. Zhang et al. show that noncollinear antiferromagnets, despite having negligible net magnetization, host a new form of spin-valley locking that substantially promotes pure spin-triplet Cooper pairing when coupled to conventional superconductors. The resulting triplet supercurrent is remarkably robust against Zeeman fields and spin canting, identifying noncollinear antiferromagnets as a promising and experimentally accessible platform for triplet superconductivity and magnetically tunable quantum technologies.

Online now: Spin-valley locking and pure spin-triplet superconductivity in noncollinear antiferromagnets proximitized to conventional superconductors #newton #physics

Quantum anomalous Hall effect with tunable Chern number in Janus Mn2Bi2Te5−xSex The quantum anomalous Hall (QAH) effect enables dissipationless edge currents without external magnetic fields, offering a promising route toward ultra-low-power electronics. Ren et al. demonstrate that Te/Se substitution induces a Janus structure in Mn2Bi2Te5, creating a tunable built-in electric field that dynamically controls the Chern number in the quantum anomalous Hall effect. The approach enables high Curie temperatures (up to 50 K) and offers a reconfigurable, energy-efficient platform for next-generation quantum and spintronic devices.

Online now: Quantum anomalous Hall effect with tunable Chern number in Janus Mn2Bi2Te5−xSex #newton #physics

Online now: Edge-exclusive domain wall motion under electric fields #newton #physics

Nonlocal magnetoelectric switching in spiral multiferroics Data centers use magnetic disks to store information. Using magnetic fields to write information leads to heating and limits device miniaturization. Spiral magnets, where spiraling of spins induces ferroelectric polarization, could allow writing directly by E-fields. Foggetti et al. find that topological constraints in spiral multiferroics lead to a nonlocal switching dynamics: spins rotate in the entire domains, not just at domain walls. This unprecedented dynamics lead to peculiar pinning and dielectric properties and imply faster switching in smaller devices.

Online now: Nonlocal magnetoelectric switching in spiral multiferroics #newton #physics

Dependence of quantum timescales on symmetry Quantum timescales are notoriously difficult to access in experiments, especially when avoiding projection on an external timescale. Experiments based on spin- and angle-resolved photoemission spectroscopy can help determine the timescale of the quantum transition in photoemission. Guo et al. present such experiments and show an increase in the quantum transition time when going from 3D to quasi-2D and quasi-1D. This indicates an intricate connection between quantum timescales and symmetry.

Online now: Dependence of quantum timescales on symmetry #newton #physics

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Feb 9 | 11:00 a.m. ET
http://dlvr.it/TQWk8Z

Roton condensation drives symmetry breaking In fractional Chern insulators, emergent particles called “rotons” can lead to new phases. Lu et al. show how condensing these rotons triggers a “smectic fractional quantum anomalous Hall” state, which breaks symmetry but keeps its topological Hall effect. The discovery reveals the rich physics possible from how excitations interact with the underlying topological order of a material.

Online now: Roton condensation drives symmetry breaking #newton #physics

Frictional contact network in dense suspension flow The microstructural underpinning of shear thickening in dense suspensions remains debated. Using a network-based approach, Sharma et al. reveal the role of different frictional constraints, especially rolling resistance, in reshaping the internal structure of dense suspensions under shear. While suspensions with different constraints may share similar viscosities, their underlying force networks differ significantly in topology. A hierarchical framework connects microscale constraints, mesoscale contact networks, and macroscopic flow, offering new insights into discontinuous shear thickening and jamming transitions in amorphous, out-of-equilibrium systems.

Online now: Frictional contact network in dense suspension flow #newton #physics

Quantum walk revivals by symmetry Quantum walks are the quantum counterparts of random walks. Steinfurth et al. demonstrate that mirror symmetries in a time-varying "coin" sequence force these walks to deterministically revive, returning to their initial state. By proving and verifying this rule with a photonic walk experiment, the researchers establish how symmetry offers direct control for quantum memory, transport, and robust state verification.

Online now: Quantum walk revivals by symmetry #newton #physics