Regulation of different ratios of Sr doping and O vacancies on the magnetic properties of anatase TiO2

Theoretical calculations on the effects of different Sr-doped ratios and oxygen vacancy concentrations on the magnetic mechanism of anatase TiO2 are rarely reported. For this problem, generalized gradient approximation (GGA) plane wave ultra-soft pseudopotential [Formula: see text]U based on the spin density functional theory framework was adopted in this work. The effect of different Sr doping ratios and O vacancy concentrations on the magnetic properties of anatase TiO2 was studied by first principles. Results show that Sr replaces Ti and O vacancies at different Sr:V[Formula: see text] ratios (1:0, 1:1, 1:2, 2:1 and 2:2), the doping system is magnetic when the Sr:V[Formula: see text] ratio is 1:2. The systems with Sr[Formula: see text]:V[Formula: see text] ratios of 1:0 and 2:1 are nonmagnetic, whereas those with 1:1, 1:2, and 2:2 Sr[Formula: see text]:V[Formula: see text] ratios are magnetic. Regardless of whether or not Sr replaces Ti and O vacancies or interstitial Sr and O vacancies in different ratios of anatase TiO2, the effect of magnetic switching can be achieved by adjusting the concentration. In this study, the largest magnetic moment of Ti[Formula: see text]Sr[Formula: see text]O[Formula: see text] system is obtained at Sr[Formula: see text]:V[Formula: see text] ratio of 2:2. The Curie temperature of the doping system is above room-temperature, and the doping system produces 100% electron spin polarizability and is half-metallized. These features are valuable to the design and preparation of novel dilute magnetic semiconductors with spin-electron injection sources. The main magnetic sources of the Ti[Formula: see text]Sr[Formula: see text]O[Formula: see text] system are the holes generated by doped Sr and O vacancy complexes, which cause the spin polarization double exchange of Ti-3d electron orbitals and O-2p electron orbits near O vacancies. This result is consistent with the average field approximation and dual exchange mechanism theories.

Atomic Vacancy Defect, Frenkel Defect and Transition Metals (Sc, V, Zr) Doping in Ti4N3 MXene Nanosheet: A First-Principles Investigation

Using first-principles calculations based on the density functional theory, the effects of atomic vacancy defect, Frenkel-type defect and transition metal Z (Z = Sc, V and Zr) doping on magnetic and electric properties of the Ti4N3 MXene nanosheet were investigated comprehensively. The surface Ti and subsurface N atomic vacancies are both energetically stable based on the calculated binding energy and formation energy. In addition, the former appears easier than the latter. They can both enhance the magnetism of the Ti4N3 nanosheet. For atom-swapped disordering, the surface Ti-N swapped disordering is unstable, and then the Frenkel-type defect will happen. In the Frenkel-type defect system, the total magnetic moment decreases due to the enhancement of indirect magnetic exchange between surface Ti atoms bridged by the N atom. A relatively high spin polarizability of approximately 70% was detected. Furthermore, the doping effects of transition metal Z (Z = Sc, V and Zr) on Ti4N3 nanosheet are explored. All doped systems are structurally stable and have relatively large magnetism, which is mainly induced by the directed magnetic exchange between surface Z and Ti atoms. Especially in the doped Ti4N3-Sc system, the high spin polarizability is still reserved, suggesting that this doped system can be a potential candidate for application in spintronics.

Anomalous plasmon modes of single-layer MoS2

The electronic plasmons of single layer MoS2 induced by different spin subbands owing to spin-orbit couplings (SOCs) are theoretically investigated. The study shows that two new and anomalous plasmonic modes can be achieved via inter-spin subband transitions around the Fermi level due to the SOCs. The plasmon modes are optic-like, which are very different from the plasmons reported recently in single-layer (SL) MoS2, and the other two-dimensional systems. The frequency of such plasmons ascends with the increasing of electron density or spin polarizability, and decreases with the increasing of wave vector. The promising plasmonic properties of SL MoS2 make it interesting for future applications in plasmonic and terahertz devices.

Novel Plasmonic Modes of Monolayer MoS$_2$ in the Presence of Spin-Orbit Interactions

We investigate on the plasmons of monolayer MoS2 in the presence of spin-orbit interactions (SOIs) under the random phase approximation. The theoretical study shows that two new and novel plasmonic modes can be achieved via inter spin sub-band transitions around the Fermi level duo to the SOIs. The plasmon modes are optic-like, which are very different from the plasmon modes reported recently in monolayer MoS2, and the other two-dimensional systems. The frequency of such plasmons increases with the increasing of the electron density or the spin polarizability, and decreases with the increasing of the wave vectors q. Our results exhibit some interesting features which can be utilized to the plasmonic and terahertz devices based on monolayer MoS2.

A Measurement of g2p at Low Q2

Jefferson Lab has been at the forefront of a program to study the polarized structure of nucleons using electron scattering. Measurements of the spin dependent structure functions, [Formula: see text] and [Formula: see text], have proven to be powerful tools in testing and understanding QCD. The neutron structure function [Formula: see text] has been measured extensively in Hall A at Jefferson Lab over a wide range of [Formula: see text], but data for [Formula: see text] remains scarce. This docment will discuss the [Formula: see text] experiment, which ran in Hall A at Jefferson Lab in the spring of 2012, and will provide the first measurement of [Formula: see text] in the resonance region; covering [Formula: see text] GeV2. The 0[Formula: see text] moment of [Formula: see text] provides a test of the Burkhardt-Cottingham sum rule, which states that the integral of [Formula: see text] over the Bjorken scaling variable [Formula: see text] goes to zero. This sum rule, valid for all values of [Formula: see text], has been satisfied for the neutron, but a violation is suggested for the proton at high [Formula: see text]. The 2[Formula: see text] moment allows for a benchmark test of [Formula: see text]PT at low [Formula: see text]. Specifically, the behavior of the longitudinally-transverse spin polarizability ([Formula: see text]), as [Formula: see text]PT calculations of this quantity deviate significantly from the measured neutron data. This document will discuss the current status of the analysis along with preliminary results.

Influence of spin polarizability on liquid gas phase transition in the nuclear matter

In this paper, we investigate the liquid gas phase transition for the spin polarized nuclear matter. Applying the lowest order constrained variational (LOCV) method, and using two microscopic potentials, AV18 and UV14+TNI, we calculate the free energy, equation of state (EOS), order parameter, entropy, heat capacity and compressibility to derive the critical properties of spin polarized nuclear matter. Our results indicate that for the spin polarized nuclear matter, the second-order phase transition takes place at lower temperatures with respect to the unpolarized one. It is also shown that the critical temperature of our spin polarized nuclear matter with a specific value of spin polarization parameter is in good agreement with the experimental result.