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<jats:p>The organic-inorganic hybrid perovskite CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> has been a good candidate for many optoelectronic applications such as light-emitting diodes due to its unique properties. Optimizing the optical properties of the CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> material to improve the device performance is a hot topic. Herein, a new strategy is proposed to enhance the light emission of CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> phosphor effectively. By adding the reactant CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>I powder in an appropriate proportion and simply grinding, the emission intensity of CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> is greatly improved. The advantages of the proposed method are swiftness, simplicity and reproducibility, and no requirement for a complex organic ligand. The mechanism of this phenomenon is revealed by x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, photoluminescence, and temperature-dependent photoluminescence. This study offers a unique insight for optimizing the optical properties of halide perovskite materials.</jats:p>

<jats:p>Lithium-excess cation disordered rock-salt materials have received much attention because of their high-capacity as a candidate for cathodes for lithium-ion batteries. The ultra-high specific capacity comes from the coordinated charge compensation of both transition metal and lattice oxygen. However, the oxygen redox at high voltage usually leads to irreversible oxygen release, thereby degrading the structure stability and electrochemical performance. Lithium-excess Li<jats:sub>1.14</jats:sub>Ni<jats:sub>0.57+0.5 <jats:italic>x</jats:italic> </jats:sub>Ti<jats:sub>0.19 – 0.5 <jats:italic>x</jats:italic> </jats:sub>Mo<jats:sub>0.10</jats:sub>O<jats:sub>2 – <jats:italic>x</jats:italic> </jats:sub>F<jats:sub> <jats:italic>x</jats:italic> </jats:sub> (<jats:italic>x</jats:italic> = 0, 0.05, 0.10, 0.15, and 0.20) with different amounts of fluorine substitution were synthesized. Among them, Li<jats:sub>1.14</jats:sub>Ni<jats:sub>0.620</jats:sub>Ti<jats:sub>0.140</jats:sub>Mo<jats:sub>0.10</jats:sub>O<jats:sub>1.85</jats:sub>F<jats:sub>0.15</jats:sub> exhibits a lower capacity decline, better rate performance, and lower structure damage. The effects of fluorine substitution on the electrochemical property and structural stability were systematic studied by x-ray photoelectron spectroscopy and <jats:italic>in situ</jats:italic> XRD etc. Results show that fluorine substitution reduces the average valence of the anion, allowing a larger proportion of low-valent redox active transition metals, increasing the transition metal redox capacity, inhibiting irreversible oxygen release and side reaction. Fluorine substitution further improves the structural stability and suppresses lattice deformation of the material.</jats:p>

<jats:p>We show that the Coulomb interaction between two circuits separated by an insulating layer leads to unconventional thermoelectric effects, such as the cooling by thermal current effect, the transverse thermoelectric effect and Maxwell’s demon effect. The first refers to cooling in one circuit induced by the thermal current in the other circuit. The middle represents electric power generation in one circuit by the temperature gradient in the other circuit. The physical picture of Coulomb drag between the two circuits is first demonstrated for the case with one quantum dot in each circuit and it is then elaborated for the case with two quantum dots in each circuit. In the latter case, the heat exchange between the two circuits can vanish. Finally, we also show that the Maxwell’s demon effect can be realized in the four-terminal quantum dot thermoelectric system, in which the quantum system absorbs the heat from the high-temperature heat bath and releases the same heat to the low-temperature heat bath without any energy exchange with the two heat baths. Our study reveals the role of Coulomb interaction in non-local four-terminal thermoelectric transport.</jats:p>

<jats:p>Iron oxide is one of the most important components in the Earth’s mantle. The recent discovery of the stable presence of Fe<jats:sub>5</jats:sub>O<jats:sub>6</jats:sub> in the Earth’s mantle environment has stimulated significant interests in understanding of this new category of iron oxides. We report the electronic structure and magnetic properties of Fe<jats:sub>5</jats:sub>O<jats:sub>6</jats:sub> calculated by the density functional theory plus dynamic mean field theory (DFT + DMFT) approach. Our calculations indicate that Fe<jats:sub>5</jats:sub>O<jats:sub>6</jats:sub> is a conductor at ambient pressure with dominant Fe-3<jats:italic>d</jats:italic> density of states at the Fermi level. The magnetic moments of iron atoms at three non-equivalent crystallographic sites in Fe<jats:sub>5</jats:sub>O<jats:sub>6</jats:sub> collapse at significantly different rates under pressure. This site-selective collapse of magnetic moments originates from the shifting of energy levels and the consequent charge transfer among the Fe-3<jats:italic>d</jats:italic> orbits when Fe<jats:sub>5</jats:sub>O<jats:sub>6</jats:sub> is being compressed. Our simulations suggest that there could be high conductivity and volume contraction in Fe<jats:sub>5</jats:sub>O<jats:sub>6</jats:sub> at high pressure, which may induce anomalous features in seismic velocity, energy exchange, and mass distribution in the deep interior of the Earth.</jats:p>

<jats:p>We construct the grand partition function of the system of massive Dirac fermions in a uniform magnetic field from Landau levels, through which all thermodynamic quantities can be obtained. Making use of the Abel–Plana formula, these thermodynamic quantities can be expanded as power series with respect to the dimensionless variable <jats:italic>b</jats:italic> = 2<jats:italic>eB</jats:italic>/<jats:italic>T</jats:italic> <jats:sup>2</jats:sup>. The zero-field magnetic susceptibility is expanded at zero mass, and the leading order term is logarithmic. We also calculate scalar, vector current, axial vector current and energy-momentum tensor of the system through ensemble average approach. Mass correction to chiral separation effect is discussed. For massless chiral fermions, our results recover the chiral magnetic effect for right- and left-handed fermions, as well as chiral separation effect.</jats:p>