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<jats:p>A novel silicon-on-insulator lateral insulated gate bipolar transistor (SOI LIGBT) is proposed in this paper. The proposed device has a P-type buried layer and a partial-SOI layer, which is called the BPSOI-LIGBT. Due to the electric field modulation effect generated by the P-type buried layer and the partial-SOI layer, the proposed structure generates two new peaks in the surface electric field distribution, which can achieve a smaller device size with a higher breakdown voltage. The smaller size of the device is beneficial to the fast switching. The simulation shows that under the same size, the breakdown voltage of the BPSOI LIGBT is 26% higher than that of the conventional partial-SOI LIGBT (PSOI LIGBT), and 84% higher than the traditional SOI LIGBT. When the forward voltage drop is 2.05 V, the turn-off time of the BPSOI LIGBT is 71% shorter than that of the traditional SOI LIGBT. Therefore, the proposed BPSOI LIGBT has a better forward voltage drop and turn-off time trade-off than the traditional SOI LIGBT. In addition, the BPSOI LIGBT effectively relieves the self-heating effect of the traditional SOI LIGBT.</jats:p>

<jats:p>Gallium nitride (GaN)-based high electron mobility transistors (HEMTs) that work in aerospace are exposed to particles radiation, which can cause the degradation in electrical performance. We investigate the effect of proton irradiation on the concentration of two-dimensional electron gas (2DEG) in GaN-based HEMTs. Coupled Schrödinger’s and Poisson’s equations are solved to calculate the band structure and the concentration of 2DEG by the self-consistency method, in which the vacancies caused by proton irradiation are taken into account. Proton irradiation simulation for GaN-based HEMT is carried out using the stopping and range of ions in matter (SRIM) simulation software, after which a theoretical model is established to analyze how proton irradiation affects the concentration of 2DEG. Irradiated by protons with high fluence and low energy, a large number of Ga vacancies appear inside the device. The results indicate that the ionized Ga vacancies in the GaN cap layer and the AlGaN layer will affect the Fermi level, while the Ga vacancies in the GaN layer will trap the two-dimensional electrons in the potential well. Proton irradiation significantly reduced the concentration of 2DEG by the combined effect of these two mechanisms.</jats:p>

<jats:p>Carbon-doped InGaAsBi films on InP:Fe (100) substrates have been grown by gas source molecular beam epitaxy (GSMBE). The electrical properties and non-alloyed Ti/Pt/Au contact resistance of n-type carbon-doped InGaAsBi films were characterized by Van der Pauw–Hall measurement and transmission line method (TLM) with and without rapid thermal annealing (RTA). It was found that the specific contact resistance decreases gradually with the increase of carrier concentration. The electron concentration exhibits a sharp increase, and the specific contact resistance shows a noticeable reduction after RTA. With RTA, the InGaAsBi film grown under CBr<jats:sub>4</jats:sub> supply pressure of 0.18 Torr exhibited a high electron concentration of 1.6 × 10<jats:sup>21</jats:sup> cm<jats:sup>−3</jats:sup> and achieved an ultra-low specific contact resistance of 1 × 10<jats:sup>−8</jats:sup> Ω⋅cm<jats:sup>2</jats:sup>, revealing that contact resistance depends greatly on the tunneling effect.</jats:p>

<jats:p>We have investigated the electronic and magnetic properties of zigzag phosphorene nanoribbons (ZPNRs) with transition metal (TM) passivated atoms, it can be found that the ZPNRs with TM passivated atoms exhibit different magnetisms except for the Ni-passivated system. Meanwhile, the results show that the magnetic moments of ZPNRs with TM passivated atoms are larger than that of ZPNRs with other passivated non-metals/groups. Interestingly, it can be found that Fe-passivated ZPNR exhibits magnetic semiconducting character, which provides the possbility for the application of phosphorene in information storage. For Mn-passivated ZPNRs, it exhibits the half-metallicity. These results may be useful for potential applications of phosphorene in electronic and high-performance spintronic devices.</jats:p>

<jats:p>The vortex pinning determining the current carrying capacity of a superconductor is an important property to the applications of superconducting materials. For layered superconductors, the vortex pinning can be enhanced by a strong interlayer interaction in accompany with a suppression of superconducting anisotropy, which remains to be investigated in iron based superconductors (FeSCs) with the layered structure. Here, based on the transport and magnetic torque measurements, we experimentally investigate the vortex pinning in two bilayer FeSCs, CaKFe<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>(Fe1144) and KCa<jats:sub>2</jats:sub>Fe<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>F<jats:sub>2</jats:sub>(Fe12442), and compare their superconducting anisotropy <jats:italic>γ</jats:italic>. While the anisotropy <jats:italic>γ</jats:italic> ≈ 3 for Fe1144 is much smaller than <jats:italic>γ</jats:italic> ≈ 15 in Fe12442 around <jats:italic>T</jats:italic> <jats:sub>c</jats:sub>, a higher flux pinning energy as evidenced by a higher critical current density is found in Fe1144, as compared with the case of Fe12442. In combination with the literature data of Ba<jats:sub>0.72</jats:sub>K<jats:sub>0.28</jats:sub>Fe<jats:sub>2</jats:sub>As<jats:sub>2</jats:sub> and NdFeAsO<jats:sub>0.82</jats:sub>F<jats:sub>0.18</jats:sub>, we reveal an anti-correlation between the pinning energy and the superconducting anisotropy in these FeSCs. Our results thus suggest that the interlayer interaction can not be neglected when considering the vortex pinning in FeSCs.</jats:p>

<jats:p>The spin Hall magnetoresistance (SMR) effect in Pt/Gd<jats:sub>3</jats:sub>Fe<jats:sub>5</jats:sub>O<jats:sub>12</jats:sub> (GdIG) bilayers was systematically investigated. The sign of SMR changes twice with increasing magnetic field in the vicinity of the magnetization compensation point (<jats:italic>T</jats:italic> <jats:sub>M</jats:sub>) of GdIG. However, conventional SMR theory predicts the invariant SMR sign in the heterostructure composed of a heavy metal film in contact with a ferromagnetic or antiferromagnetic film. We conclude that this is because of the significant enhancement of the magnetic moment of the Gd sub-lattice and the unchanged moment of the Fe sub-lattice with a relatively large field, meaning that a small net magnetic moment is induced at <jats:italic>T</jats:italic> <jats:sub>M</jats:sub>. As a result, the Néel vector aligns with the field after the spin-flop transition, meaning that a bi-reorientation of the Néel vector is produced. Theoretical calculations based on the Néel’s theory and SMR theory also support our conclusions. Our findings indicate that the Néel-vector direction of a ferrimagnet can be tuned across a wide range by a relatively low external field around <jats:italic>T</jats:italic> <jats:sub>M</jats:sub>.</jats:p>

<jats:p>The magnetic field provided by magnetized SrFe<jats:sub>12</jats:sub>O<jats:sub>19</jats:sub> particles in FeSi/SrFe<jats:sub>12</jats:sub>O<jats:sub>19</jats:sub> composites is used to replace the applied transverse magnetic field, which successfully reduces the magnetic loss of the composites with minor reduction of permeability. This magnetic loss reduction mainly comes from the decrease in hysteresis loss, while the eddy current loss is basically unaffected. The hysteresis loss reduction in magnetized composites is believed to be due to the decrease in domain wall displacement caused by the increase in the average magnetic domain size in a DC magnetic field. This is an effective method for reducing the magnetic loss of soft magnetic composites with wide application potential, and there is no problem of increasing the cost and the volume of the magnetic cores.</jats:p>

<jats:p>Two-dimensional (2D) magnets provide an ideal platform to explore new physical phenomena in fundamental magnetism and to realize the miniaturization of magnetic devices. The study on its domain structure evolution with thickness is of great significance for better understanding the 2D magnetism. Here, we investigate the magnetization reversal and domain structure evolution in 2D ferromagnet Fe<jats:sub>3</jats:sub>GeTe<jats:sub>2</jats:sub> (FGT) with a thickness range of 11.2–112 nm. Three types of domain structures and their corresponding hysteresis loops can be obtained. The magnetic domain varies from a circular domain via a dendritic domain to a labyrinthian domain with increasing FGT thickness, which is accompanied by a transition from squared to slanted hysteresis loops with reduced coercive fields. These features can be ascribed to the total energy changes from exchange interaction-dominated to dipolar interaction-dominated with increasing FGT thickness. Our finding not only enriches the fundamental magnetism, but also paves a way towards spintronics based on 2D magnet.</jats:p>

<jats:p>Following the gradual maturation of synthetic techniques for nanomaterials, exciton–plasmon composites have become a research hot-spot due to their controllable energy transfer through electromagnetic fields on the nanoscale. However, most reports ignore fluorescence resonance energy transfer (FRET) under electrostatic repulsion conditions. In this study, the FRET process is investigated in both electrostatic attraction and electrostatic repulsion systems. By changing the Au : quantum dot ratio, local-field induced FRET can be observed with a lifetime of ns and a fast component of hundreds of ps. These results indicate that the intrinsic transfer process can only elucidated by considering both steady and transient state information.</jats:p>

<jats:p>Nonlinear optical frequency mixing, which describes new frequencies generation by exciting nonlinear materials with intense light field, has drawn vast interests in the field of photonic devices, material characterization, and optical imaging. Investigating and manipulating the nonlinear optical response of target materials lead us to reveal hidden physics and develop applications in optical devices. Here, we report the realization of facile manipulation of nonlinear optical responses in the example system of MoS<jats:sub>2</jats:sub> monolayer by van der Waals interfacial engineering. We found that, the interfacing of monolayer graphene will weaken the exciton oscillator strength in MoS<jats:sub>2</jats:sub> monolayer and correspondingly suppress the second harmonic generation (SHG) intensity to 30% under band-gap resonance excitation. While with off-resonance excitation, the SHG intensity would enhance up to 130%, which is conjectured to be induced by the interlayer excitation between MoS<jats:sub>2</jats:sub> and graphene. Our investigation provides an effective method for controlling nonlinear optical properties of two-dimensional materials and therefore facilitates their future applications in optoelectronic and photonic devices.</jats:p>