New Research in Physics

Abstract By using first-principles calculations based on density functional theory, the electronic and optical properties of α-PbO monolayer were investigated. In this study, three different approximations were used, i.e. DFT-PBE hybrid function, mBJ and HSE06. By evaluating the electronic parameters of the single layer, it is clear that this two-dimensional single layer material shows semiconductor behavior, and has an average direct band gap of 2.55 (2.50 eV, 2.70 eV) which is calculated at the PBE level of theory (mBJ, HSE06) and can be effectively controlled by strain effects. The analysis of the optical properties shows that the α-PbO monolayer acts as a nearly transparent material in the visible light range, however, it shows good absorption and reflection in the ultraviolet range of the electromagnetic spectrum. In addition, calculations show that uniaxial and biaxial strain scanning effectively modulates the optical properties of α-PbO monolayer. The calculated excellent electronic and optical properties show that the two-dimensional α-PbO monolayer can be used in nano-optoelectronic technologies.

Abstract In the present research, we addressed the movement of ionic carriers inside perovskite, which was used as an active layer in the structure. These carriers can lead to the creation of hysteresis in the cyclic voltammetry diagram of the device. Other layers of the device, including the metal contacts, can also play a role in the currents. To investigate this issue, we investigated the role of aluminum metal contact. In addition, we placed a Spiro-OMeTAD layer between the metal contact and the perovskite and investigated its role in the device's behavior. According to the results of the cyclic voltammetry analysis, a peak was observed in the absence of radiation in the diagrams, which can be attributed to the occurrence of a Redox reaction in the structure. Because the ions are mobile in the structure, as a result of this movement, the iodine ions move towards the metal contact of aluminum and react with aluminum to form aluminum iodide. This type of behavior (related to the peak of Redox reaction) in this device is called capacitive behavior, which is not desirable for memristor devices. There is a type of behavior called inductive behavior, which is desirable for memristors and was not observed in the fabricated devices.

Abstract The importance of accurate, instantaneous and non-contact temperature measurement in inaccessible or dangerous places has led to a significant expansion of research for the development of nanophotonic temperature sensors. In this article, the temperature of natural gas liquids (NGL) is measured instantaneously and non-contactly by examining the temperature-dependent radiation intensity of core-shell lanthanide frequency upconversion nanoparticles Ba2LuF7:Yb3+, Nd3+, Er3+@Ba2LaF7. These 30 nm nano emitters emit a photon in the green region by absorbing the radiation of several 980 nm photons. Therefore, after characterizing the nanoparticles, by examining the temperature performance of the core-shell cubic phase nano materials doped with lanthanide ions, with Ba2LuF7 matrix and Er3+/Yb3+/Nd3+ doped ions as the core and Ba2LaF7 as the shell, the working function of this sensor is It was obtained that it was used to measure the temperature of natural gas liquids in the range of 15 to 30 degrees Celsius with a temperature sensitivity of K-10.0016.

Abstract In this work, using the transfer matrix method and considering the Rashba spin-orbit interaction in the ZnSe/ZnMnSe/ZnSe/ZnMnSe/ZnSe heterostructures, the thickness effects of ZnMnSe and ZnSe layers on spin current density and shot noise is investigated. Results show that ZnMnSe thickness has a crucial role in spin polarization, in which spin current and shot noise for a spin up shows increasing with oscillation behavior while for a spin down shows a monotonically decreasing trend. Moreover, the effect of Rashba on spin up and spin down is to increase and decrease the height potential, respectively, which consequently causes to decrease and increase of spin current and shot noise in spin up and down, respectively.

Abstract Calculating bond states, mass spectrum, spin-orbits coupling, wavefunction, and energy levels is an important part of the challenges facing hyperclear physics. There is currently no complete and practical method for obtaining the parameters mentioned in light and heavy hypernuclei; On the other hand, the available relations do not include the relativistic effects of the interaction on all the physical parameters of the constrained structure. Therefore, due to the importance of the subject, in this article, we will analyze the challenge by referring to the principles of quantum field theory and the method of oscillator representation and its normalization of creation and annihilation operators. The proposed solution, considering the relativistic effects of the bound system, is presented as a mass-potential plugging for calculating the parameters of hypernuclei. The most important theoretical achievement presented in this paper is relativistic corrections on the mass and interaction potential of hypernuclei, which so far in other research studies, the results of relativistic effects have not been considered.

Abstract In recent years, there has been an increasing interest in using plasmonic nanoparticles as thermal nano sources with the ability to be controlled remotely by light, which has led to the emergence of thermoplasmonics science. In this regard, nanoparticles with different shapes, compositions, and materials can create limited heat generation at the nanoscale. Therefore, in this article, the plasmonic and thermoplasmonic properties of asymmetric hexagonal heterodimer nanoparticles of Ag-Au, Cu-Ag, and Cu-Au compositions have been investigated. The isosbestic points and the coupling energy due to the gap created in the plasmonic modes of the absorption spectrum due to the change in the polarization of the light have been investigated and calculated. The obtained results show that with the combination of heterogeneous binary nanoparticles of silver and copper in light polarization parallel to the dimer axis, the electric field can be strengthened up to 293 times, and the highest temperature change in Ag-Au heterogeneous binary nanoparticles with a value of ∆Tmax=417℃ in L polarization is related.