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In this paper, we present a theoretical perspective regarding the interaction of graphene with circularly polarized light and magnetic field, from the topological insulators point of view. We analyze how these two external fields affect the spectral, topological and transport properties of graphene and correlate the findings in order to explain in a fundamental and unified way the emerging topological phase transitions. In this respect, in the first step we introduce a model for interaction and charge transport. Then, based on the derived theory, we present numerical results aimed to explain the underlying processes which give graphene topological properties. The central point is represented by the time-reversal symmetry breaking which generates chiral edge states, namely electronic states localized at the edges of the system, having opposite velocity directions. We find that the light frequency, intensity and polarization state drastically influence the formation of the chiral edge states and their number. We correlate this effect with quantum Hall transport, analyzing the resulting transversal (Hall) resistance plateaus and their values. Moreover, if a supplementary magnetic field driving is applied, there emerge intricate topological phase transitions, characterized by introducing or removing specific Hall resistance plateaus.

The concept of laser mutagenesis of plants has become widespread in Russia and abroad. The reason is that the stimulation effect caused by coherent light persisted, in some cases, for several (two to nine) vegetation periods and was even inherited. However, the parameters of the acting factor did not correspond to the conditions of induced genetic variability. To test the hypothesis of the mutagenic effect of low-intensity laser radiation in the visible spectrum region, sterile explants of blackberry and red raspberry (Rubus idaeus L.) were treated with quasi-monochromatic (coherent) light and cultured in vitro according to the standard technique for 30–90 days. The radiation sources were a helium-neon laser generating at a wavelength of 632.8 nm and LEDs with spectral line maxima of 660 and 740 nm. Irradiation was carried out for 60, 120, 240, 480, and 960 s at a power density of 2–6 W/m2. The number and length of shoots formed on each explant were measured with an interval of 10 days. Red (632.8 or 660 nm) quasi-monochromatic light exposure accelerated the growth processes. For example, the average number of shoots formed on one explant in blackberries after 20 days of cultivation reached 1.2 in the variant with irradiation, while it was 0.39 in the control variant (without irradiation). Far-red light (740 nm) caused the opposite reaction. After 30 days of vegetation, the number and length of shoots formed were 1.5 times less than in the nonirradiated variant. The photoinduced effect of stimulation or inhibition due to phytochrome photoconversion remained clearly visible and mathematically significant (Р > 0.98) for 30–50 days of cultivation. In a later period, the differences with the control variant smoothed out and became statistically unreliable. The limited time of phenotypic variability retention indicates that it is maintained not at the genetic but at the epigenetic level. Consequently, the hypothesis of the mutagenic effect of low-intensity laser radiation is untenable. [ABSTRACT FROM AUTHOR]

Photo enhanced oxygen evolution reaction has recently emerged as an advanced strategy with great application prospects for highly efficient energy conversion and storage. In the course of photo enhanced oxygen evolution reactions, the other works focus has predominantly centered on catalysts while inadvertently overlooking the pivotal role of photo. Consequently, this manuscript embarks upon a comprehensive review of recent advancements in photo-driven, aiming to illuminate this critical dimension. A detailed introduction to the photothermal effect, photoelectronic effect, photon-induced surface plasmon resonance, photo and heterojunction, photo-induced reversible geometric conversion, photo-induced energy barrier reduction, photo-induced chemical effect, photo-charging, and the synthesis of laser/photo-assisted catalysts, offering prospects for the development of each case is provided. A detailed introduction to the photothermal effect, photoelectronic effect, photon-induced surface plasmon resonance, photo and heterojunction, photo-induced reversible geometric conversion, photo-induced energy barrier reduction, photo-induced chemical effect, photo-charging, and the synthesis of laser/photo-assisted catalysts is provided. At the same time, the overpotential and Tafel slope of some catalysts mentioned above at 10 mA cm -2 is collected, and calculated the lifting efficiency of light on them, offering prospects for the development of each case., (© 2024 Wiley‐VCH GmbH.)

Based on the photoinduced photothermal, photoelectric, and photocatalytic effects of black phosphorus (BP) nanosheets, a BP‐PAO fiber with enhanced uranium extraction capacity and high antibiofouling activity is fabricated by compositing BP nanosheets into polyacrylamidoxime (PAO). The photothermal effect increases the coordination interaction between UO22+ and the functional amidoxime group, and the photoelectric effect produces the surface positive electric field that exhibits electrostatic attraction to the negative [UO2(CO3)3]4−, which all increase the capacity for uranium adsorption. The photocatalytic effect endows the adsorbent with high antibiofouling activity by producing biotoxic reactive oxygen species. Owing to these three photoinduced effects, the photoinduced BP‐PAO fiber shows a high uranium adsorption capacity of 11.76 mg g−1, which is 1.50 times of the PAO fiber, in bacteria‐containing natural seawater. [ABSTRACT FROM AUTHOR]

In this paper, we present a theoretical perspective regarding the interaction of graphene with circularly polarized light and magnetic field, from the topological insulators point of view. We analyze how these two external fields affect the spectral, topological and transport properties of graphene and correlate the findings in order to explain in a fundamental and unified way the emerging topological phase transitions. In this respect, in the first step we introduce a model for interaction and charge transport. Then, based on the derived theory, we present numerical results aimed to explain the underlying processes which give graphene topological properties. The central point is represented by the time-reversal symmetry breaking which generates chiral edge states, namely electronic states localized at the edges of the system, having opposite velocity directions. We find that the light frequency, intensity and polarization state drastically influence the formation of the chiral edge states and their number. We correlate this effect with quantum Hall transport, analyzing the resulting transversal (Hall) resistance plateaus and their values. Moreover, if a supplementary magnetic field driving is applied, there emerge intricate topological phase transitions, characterized by introducing or removing specific Hall resistance plateaus. • Circularly polarized light induces a topological phase transition in graphene. • Hall resistance plateaus may be observed when circularly polarized light is applied. • The light intensity, energy and polarization state affect the Hall conductance. • A supplementarymagnetic field induces intricate topological phase transitions. [ABSTRACT FROM AUTHOR]

A molecular design for the electret material of n -operating organic field-effect transistor-based (OFET) memories is introduced. A large memory window and high operating speed were achieved while the polar groups are connected to the polymer chain of polyimide, which plays the role of electret of a transistor memory device. The phase variation of electrical force microscopy images showed that polarization field induces charge trapping states on the surface of electret layer and accumulates charged carriers within the conducting channel of OFET to achieve high-performance memory and transistor simultaneously. An extra-large memory window was also obtained by introducing photo-induced charge transfer effect. [ABSTRACT FROM AUTHOR]

Abstract: We have established a principal possibility of changes of the light reflectivity at the wavelength of 633nm (He–Ne laser) under influence of the external laser light. The changes are very sensitive to the wavelength of the photoinduced laser. We have chosen two types of the photoinduced lasers: UV nitrogen 7ns laser at wavelength 371nm heating near the absorption edge and the 10ns 1064nm Nd:YAG laser with wavelength 1064nm. The power dependences of the reflectivity were studied. Possible explanation of the observed effects is presented following the conception of the nano-trapping levels. These results have been obtained from two ZnO thin films prepared from principally different deposition parameters leading to different particle features and morphologies. [Copyright &y& Elsevier]

Abstract: Photoinduced vector deformations in amorphous Se films on viscous and rigid substrates have been studied for comparison with those in As2S3. In both the films, illumination of focused and unfocused linearly-polarized bandgap light produces, respectively, anisotropic M-shape deformations and wavy wrinkles. The M-deformations occur in parallel to the electric field, but the wavy directions are contrastive; parallel and orthogonal to the electric field in Se and As2S3 films on grease. The unfocused illumination also produces corrugations in As2S3 films on glass substrates. We assume that atomic and optical forces are responsible for these deformations. [Copyright &y& Elsevier]

Abstract: We report a fabrication of high-density nanodots by photodoping in overdoped Bi2Sr2CaCu2O8+d thin film (T c =80K). A scanning near-field optical microscope probe is used to locally excite carrier and photodoped region is associated with lower T c phase (T c =75K) via overdoping. Nanoscale characterizations with optical reflectivity reveal that nanodots (30-nm-diameter) are regularly distributed in 50nm step. The resultant films with photoinduced nanodots enhance J c (at least 5 times larger than the initial one), a situation being similar to strong pinning effects observed in films modified by either ion irradiation or sputtered nanoparticles. These results suggest that photoinduced nanodots with lower T c act as effective pinning centers. [Copyright &y& Elsevier]

We have investigated the photoinduced transformation of C60 film in air at 300 K by means of Raman scattering spectroscopy and atomic force microscopy (AFM). In the Raman experiments, we have observed a new Raman band at 1426 cm-1, which is absent in the photoinduced polymerized C60 phase. Furthermore, we have investigated the surface structure of the C60 film with variation of the photo-irradiation time in air by using AFM, and have found some lamella-like structures. We have ascribed the 1426 cm-1 band and the lamella-like structures to the formation of fragmentary graphite in the surface of C60 film. [ABSTRACT FROM AUTHOR]

A gigantic enhancement of the dielectric constant by UV light illumination is calculated in the electron-lattice theory in quantum paraelectrics of perovskite oxides, such as SrTiO 3 and KTaO 3 , under a weak DC electric field. The temperature dependence of the gigantic real part of the dielectric constant ε UVDC of SrTi 16 O 3 under both UV light and DC electric fields is calculated in satisfactory agreement with the experiment. The dependences of the relative ratio of ε UVDC /ε at 5 K on UV intensity under DC of 40 V/mm and at various bias DC electric field under a constant UV irradiation of 1.6 · 10 15 photons/cm 2 s are obtained in the electron-lattice theory in agreement with the experiment. [ABSTRACT FROM AUTHOR]

Photoinduced and second-order optical effects in the interfaces separating InBr (IB) films doped by Al, In, Sn and bare glass substrates were investigated using the photoinduced optical second harmonic generation. The second-order optical susceptibilities (at λ=1.76 μm) show a good correlation with the shift of the absorption edge. The maximal response of the photoinduced response signal was observed for the pump-probe delaying times equal about 32 ps. The measurements indicate that the observed effects are caused by two cases: by interface potential gradients on the border glass-IB and by polarization of the medium due to impurities. The observed phenomenon may be proposed as a sensitive tool for investigations of thin nanointerfaces appearing between the glass substrate and crystallite layers. [Copyright &y& Elsevier]

The peculiarities of optical absorption of octahedral ions Fe2+ and Fe4+ have been analyzed at various parameters of a trigonal and non-trigonal field by taking into account the transitions between levels of a split ground state. The spectral dependence of optical absorption coefficient on parameters of a crystal field has been constructed. The differences of optical absorption spectra that arise with redistribution and change of quantity of ions Fe2+ and Fe4+ have been considered. The explanation of experimental results on photoinduced changes of optical absorption in yttrium ferrite garnet single crystals has been proposed. [Copyright &y& Elsevier]

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Abstract: The possibility of coherent laser induced enhanced charge density acentricity in the layered single crystals of CdBr2 is demonstrated experimentally. The possible manipulation through non-centrosymmetry was achieved by introduction of the I ion dopants which perform some kind of intercalation. The effects show strong dependence on hydrostatic pressure and are detected by second order nonlinear optical effects as well as by piezoelectricity. The proposed method opens a new opportunity for formation charge density acentricity on the nano level. More important is that the corresponding technology is relatively cheap. [Copyright &y& Elsevier]

Abstract: A transient effect induced by an irradiation treatment using a cw green (532nm) laser or a microsecond pulsed CO2 laser at 10.6μm was observed on the absorbance and on the refractive refractive index in the visible spectral range. We have found modifications of absorption and refractive index in visible range which relax and disappear after the power cut of irradiation. Two main mechanisms participate in the observed photo-induced effects: the polarization of trapping states within the energy band-gap should be due to pure electronic contribution and/or related to the phonon sub-system manifesting through electron–phonon interactions. The relaxation of the photo-induced changes, after switching off the laser treatment, is also studied. [Copyright &y& Elsevier]

The effect of linearly polarized light on the metamagnetic phase transition in the antiferromagnetic Ca3Mn2Ge3O12 garnet was studied. The photoinduced change of the transition field has been found. The observed effect is related to the magnetic moment that arises in this antiferromagnetic under illumination. [Copyright &y& Elsevier]