Linear Magnetoelectric Phase in Ultrathin MnPS₃ Probed by Optical Second Harmonic Generation

The transition metal thiophosphates MPS₃ (M=Mn, Fe, Ni) are a class of van der Waals stacked insulating antiferromagnets that can be exfoliated down to the ultrathin limit. MnPS₃ is particularly interesting because its Néel ordered state breaks both spatial-inversion and time-reversal symmetries, allowing for a linear magnetoelectric phase that is rare among van der Waals materials. However, it is unknown whether this unique magnetic structure of bulk MnPS₃ remains stable in the ultrathin limit. Using optical second harmonic generation rotational anisotropy, we show that long-range linear magnetoelectric type Néel order in MnPS₃ persists down to at least 5.3 nm thickness. However an unusual mirror symmetry breaking develops in ultrathin samples on SiO₂ substrates that is absent in bulk materials, which is likely related to substrate induced strain

High sensitivity bolometers based on metal nanoantenna dimers with a nanogap filled with vanadium dioxide

One critical factor for bolometer sensitivity is efficient electromagnetic heating of thermistor materials, which plasmonic nanogap structures can provide through the electric field enhancement. In this report, using finite element method simulation, electromagnetic heating of nanorod dimer antennas with a nanogap filled with vanadium dioxide (VO2) was studied for long-wavelength infrared detection. Because VO2 is a thermistor material, the electrical resistance between the two dimer ends depends on the dimer's temperature. The simulation results show that, due to the high heating ability of the nanogap, the temperature rise is several times higher than expected from the areal coverage. This excellent performance is observed over various nanorod lengths and gap widths, ensuring wavelength tunability and ultrafast operating speed, thereby making the dimer structures a promising candidate for high sensitivity bolometers

Increased Transforming Growth Factor-beta1 in Alcohol Dependence

Ethanol and its metabolite acetaldehyde increase transforming growth factor beta1 (TGF-β1) expression in animal studies. TGF-β1 is related with the hepatic stellate cell (the key element of hepatic fibrogenesis) and the radial glia (the key element of neuronal migration). Blood samples were collected from 41 patients with alcohol dependence, TGF-β1 levels measured by ELISA were compared with 41 normal subjects. Plasma TGF-β1 levels in the patients with alcohol dependence (1,653.11±532.45 pg/mL) were significantly higher than those of healthy subjects (669.87±366.53 pg/mL) (P=0.000). Patients with or without liver pathology showed no difference in TGF-β1 (P=0.36). Increased TGF-β1 may mediate deleterious effect of alcohol such as hepatic fibrosis and suppressed neuronal developments in alcohol dependence patients

Optical slot antennas and their applications to photonic devices

We present optical slot antennas and their applications to photonic devices. We show that metallic nanoslots have the properties of a slot antenna by measuring the transmission spectra and far-field radiation patterns and then prove that they can be physically regarded as magnetic dipoles in the optical region. Additionally, we can generate directional radiations from optical slot antennas by adopting the geometry of radiofrequency Yagi-Uda antenna and properly adding auxiliary elements called reflectors and directors to a single slot antenna. We present two cases as the applications of optical slot antennas. One is the integration of slot antennas to plasmonic waveguides. This combination can be used as a basic unit for optical interconnection to free space and plasmonic via in multilayered plasmonic structures. The other is the integration of slot antennas to the electrode of light-emitting diodes (LEDs). Using slot antennas, we can control the polarization and direction of emissions from LEDs. Besides the above-mentioned two cases, we expect that optical slot antennas have possible applications to various photonic devices and can be essential elements in future integrated photonic circuits with nanometer scales

Linear Magnetoelectric Phase in Ultrathin MnPS_{3} Probed by Optical Second Harmonic Generation

The transition metal thiophosphates MPS_{3} (M=Mn, Fe, Ni) are a class of van der Waals stacked insulating antiferromagnets that can be exfoliated down to the ultrathin limit. MnPS_{3} is particularly interesting because its Néel ordered state breaks both spatial-inversion and time-reversal symmetries, allowing for a linear magnetoelectric phase that is rare among van der Waals materials. However, it is unknown whether this unique magnetic structure of bulk MnPS_{3} remains stable in the ultrathin limit. Using optical second harmonic generation rotational anisotropy, we show that long-range linear magnetoelectric type Néel order in MnPS_{3} persists down to at least 5.3 nm thickness. However an unusual mirror symmetry breaking develops in ultrathin samples on SiO_{2} substrates that is absent in bulk materials, which is likely related to substrate induced strain. © 2020 American Physical Society11sciescopu

Alkali Metal Ion Substituted Carboxymethyl Cellulose as Anode Polymeric Binders for Rapidly Chargeable Lithium-Ion Batteries

The increasing demand for short charging time on electric vehicles has motivated realization of fast chargeable lithium-ion batteries (LIBs). However, shortening charging time of LIBs is limited by Li+ intercalation process consisting of liquid-phase diffusion, de-solvation, SEI crossing, and solid-phase diffusion. Herein, we propose a new strategy to accelerate de-solvation step through control of interaction between polymeric binder and solvent-Li+ complexes. For this purpose, three alkali metal ions (Li+, Na+, and K+) substituted carboxymethyl cellulose (Li-, Na-, and K-CMC) are prepared to examine the effects of metal ions on their performance. The lowest activation energy of de-solvation and the highest chemical diffusion coefficient were observed for Li-CMC. Specifically, Li-CMC cell with a capacity of 3 mAh cm-2 could be charged to \u3e95% in 10 min, while a value above \u3e85% was observed after 150 cycles. Thus, the presented approach holds great promise for the realization of fast charging

Modulation of the Dirac Point Voltage of Graphene by Ion-Gel Dielectrics and Its Application to Soft Electronic Devices

We investigated systematic modulation of the Dirac point voltage of graphene transistors by changing the type of ionic liquid used as a main gate dielectric component. Ion gels were formed from ionic liquids and a non-triblock-copolymer-based binder involving UV irradiation. With a fixed cation (anion), the Dirac point voltage shifted to a higher voltage as the size of anion (cation) increased. Mechanisms for modulation of the Dirac point voltage of graphene transistors by designing ionic liquids were fully understood using molecular dynamics simulations, which excellently matched our experimental results. It was found that the ion sizes and molecular structures play an essential role in the modulation of the Dirac point voltage of the graphene. Through control of the position of their Dirac point voltages on the basis of our findings, complementary metal–oxide–semiconductor (CMOS)-like graphene-based inverters using two different ionic liquids worked perfectly even at a very low source voltage (<i>V</i>_DD = 1 mV), which was not possible for previous works. These results can be broadly applied in the development of low-power-consumption, flexible/stretchable, CMOS-like graphene-based electronic devices in the future

Alkali Metal Ion Substituted Carboxymethyl Cellulose as Anode Polymeric Binders for Rapidly Chargeable Lithium-Ion Batteries

The increasing demand for short charging time on electric vehicles has motivated realization of fast chargeable lithium-ion batteries (LIBs). However, shortening charging time of LIBs is limited by Li+ intercalation process consisting of liquid-phase diffusion, de-solvation, SEI crossing, and solid-phase diffusion. Herein, we propose a new strategy to accelerate de-solvation step through control of interaction between polymeric binder and solvent-Li+ complexes. For this purpose, three alkali metal ions (Li+, Na+, and K+) substituted carboxymethyl cellulose (Li-, Na-, and K-CMC) are prepared to examine the effects of metal ions on their performance. The lowest activation energy of de-solvation and the highest chemical diffusion coefficient were observed for Li-CMC. Specifically, Li-CMC cell with a capacity of 3 mAh cm-2 could be charged to &gt;95% in 10 min, while a value above &gt;85% was observed after 150 cycles. Thus, the presented approach holds great promise for the realization of fast charging. This article is protected by copyright. All rights reserved.TRU