Abstract HfO2-based dielectrics engineered into an MPB-like regime have emerged as promising candidates for next-generation dynamic random-access memory (DRAM) capacitors because they offer enhanced dielectric permittivity while preserving the wide bandgap and CMOS compatibility of fluorite-structured oxides. At the nanometer-scale film thicknesses and grain dimensions relevant to DRAM, surface and interface energies, electrode confinement, stress, and defect distributions strongly reshape the relative stability and accessibility of fluorite-derived phases. However, the physical origin of the high-k response and its relationship with leakage current and reliability remain under active discussion. In this review, we summarize recent progress in HfO2-based MPB dielectrics from three perspectives. First, we discuss two complementary interpretations of dielectric enhancement: spatial phase coexistence between orthorhombic and tetragonal phases at the MPB, and dynamic nonlinear dielectric response associated with low transition barriers and field-induced structural evolution. Second, we review major engineering strategies for achieving MPB-like behavior, including stoichiometric and oxygen-vacancy control, advanced annealing processes, doping, bilayer and superlattice heterostructures, and electrode/interface engineering. Third, we evaluate the practical performance and reliability requirements for DRAM applications, with emphasis on the coupled trade-offs among dielectric constant, leakage current, equivalent oxide thickness, and time-dependent dielectric breakdown. Representative reports include k ≈ 67 with a leakage current density of 3 × 10−8 A/cm2 at 0.8 V and, in a separate ultrathin HZO device, an EOT of approximately 2.42 Å with k ≈ 64.24. Finally, we highlight that the optimization of MPB HfO2-based dielectrics requires a holistic design framework that simultaneously considers phase stability, defect dynamics, interface quality, and realistic low-voltage benchmarking conditions.
Abstract Over the years, magnetic nanoparticles (MNPs) have evolved from passive imaging and delivery agents into active transducers that convert externally applied magnetic fields into localized biological stimuli. This transition has created opportunities for magnetogenetics, in which MNPs serve as remotely controlled biointerfaces for regulating cellular activity, tissue function, and therapeutic responses. In this review, we discuss MNP transducers for magnetogenetics from the perspective of materials design, biointerface engineering, and transduction mechanisms. We start with magnetothermal transduction, where nanoparticles dissipate heat under alternating magnetic fields (AMFs) to activate thermosensitive ion channels such as TRPV1, enabling wireless neuronal activation, deep brain stimulation (DBS), regenerative signaling, and disease therapy. We then discuss magnetomechanical transduction, where nanoparticles, nano/micro-discs, nanochains, etc., generate forces, torques, oscillations, or matrix deformation to activate mechanosensitive channels, integrin-mediated pathways, stem cell differentiation, immune modulation, and tumor inhibition. Next, we examine magnetoelectric transduction, where magnetostrictive-piezoelectric materials convert magnetic inputs into local electric fields or surface potentials for neural stimulation, DBS, nerve regeneration, and wound healing. Across these modalities, biological outcomes are governed by intrinsic magnetic properties and several other factors, including particle geometry, anisotropy, surface chemistry, protein corona formation, tissue retention, field waveform, and proximity to the biological target. We further comment on key design principles, including mechanism-specific dosimetry, geometry-field co-design, biointerface localization, targeting specificity, clearance, and chronic safety. Finally, we highlight opportunities for purpose-built, programmable, and closed-loop magnetic biointerfaces that integrate material architecture, magnetic-field input, and biological target selection for precise control of cellular and tissue function.
Abstract (GaP1−xNx)n(GaP1−yAsy)m heterostructures lattice-matched (LM) with Si are interesting for the integration of optoelectronic devices or solar cells (SCs) with standard Si technology. The growth and properties of 50-period (GaP1−xNx)n(GaP1−yAsy)m superlattices that are grown epitaxially on nominally (001)-oriented Si substrates are reported, using gaseous precursors in ultra-high vacuum. These heterostructures are expected to exhibit type-II band alignment because of the addition of N or As to GaP, the former reducing the conduction band energy while the latter increases the valence band energy. Two short-period superlattices with n = 12 and m = 4 monolayers, with different N and As mole fractions are designed and grown, intended to be LM with Si. The results show the high structural quality of these superlattices, with no extended defects such as dislocations, twins or stacking faults observed in the TEM-examined regions. Both samples show intense near-band-edge photoluminescence with room temperature bandgap energies in the range 1.8 to 1.9 eV. The absorption coefficient spectrum exhibits a direct band-like behavior near the absorption edge, approaching to a plateau with values in the range α ∼ 2 × 104 cm−1 above the absorption edge, which are comparable to those obtained for high efficiency SC materials.
Abstract Although remarkable advances in cancer treatment have led to longer survival, mortality associated with tumors has shown only limited reduction over the past few decades. In recent years, photoimmunotherapy (PIT) has emerged as a promising therapeutic paradigm that integrates thermal ablation and immunotherapy for synergistic antitumor effects. In addition to directly killing tumor cells via thermal ablation, this approach also activates the host immune response. However, poor tumor targeting, off-target release of the therapeutic agent, and non-specific immune effects hinder the clinical translation of PIT. To address these issues, temperature-sensitive “smart” nanocarriers that could selectively release the therapeutic load in a controlled manner have been reported. Among these, those that are responsive to mild hyperthermia have attracted significant attention, as these nanocarriers not only enhance tumor accumulation but also induce immune activation in the tumor microenvironment. Furthermore, PIT involves PDT/PTT-combined immunotherapy, targeted photo-immunoadjuvants, and nanomedicine-based delivery systems that integrate immune checkpoint blockade and cancer vaccines. This review summarises recent progress in temperature-responsive nanoplatforms for PTT-based immunotherapy. These nanoplatforms focus on molecular design, nanoengineering strategies, immune modulation mechanisms, and the potential to overcome therapeutic resistance at both preclinical and clinical levels.
Abstract MXenes have emerged as promising two-dimensional nanomaterials for cancer nanomedicine owing to their tunable surface chemistry, strong photothermal response, and favorable biocompatibility. Herein, we develop a gold nanoparticles-decorated MXene nanoplatform (Au@Mo2TiC2Tx-PEG) for synergistic photothermal and catalytic tumor therapy. The nanoplatform is constructed by anchoring Au nanoparticles onto Mo2TiC2Tx nanosheets, followed by polyethylene glycol modification to improve physiological stability and biocompatibility. The as-prepared Au@Mo2TiC2Tx-PEG exhibits strong near-infrared absorption with a photothermal conversion efficiency of 39.8%, enabling effective photothermal therapy under 808 nm laser irradiation. Notably, this nanoplatform possesses intrinsic glucose oxidase (GOx)-like and peroxidase (POD)-like activities, which initiate a cascade catalytic reaction within the tumor microenvironment. Glucose oxidation-mediated H2O2 generation, which subsequently converts into highly cytotoxic reactive oxygen species, while simultaneously depleting intracellular glutathione disrupts tumor redox homeostasis. The integrated catalytic and photothermal effects synergistically enhance oxidative stress, promote tumor cell apoptosis, and improve therapeutic efficacy. Both in vitro and in vivo studies reveal that Au@Mo2TiC2Tx-PEG effectively suppresses tumor progression, achieving a tumor inhibition rate of 94% under 808 nm laser irradiation with minimal systemic toxicity. These findings demonstrate the potential of the MXene-based nanoplatform to integrate catalytic metabolism regulation and photothermal activation, providing a powerful strategy for precision cancer therapy.
