Thermoelectric, spin-dependent optical and quantum transport properties of 2D half-metallic Co2Se3.

In this paper, the thermoelectric, spin-dependent optical and quantum transport properties of a two-dimensional (2D) Co2Se3 monolayer are investigated using first principles calculations. The stability of the Co2Se3 monolayer is confirmed by energy-cohesive calculations and phonon dispersion analysis. According to electronic and magnetic calculations, Co2Se3 is a Dirac half-metal (DHM) with several Dirac cones around the Fermi level in the spin-down channel and exhibits intrinsic ferromagnetism with a high Curie temperature. Investigation of the thermoelectric properties shows that the Co2Se3 monolayer with ZT ∼ 1 at low temperature (T < 300 K) to medium temperature (500 < T < 700 K) can be introduced as a suitable candidate for thermoelectric applications. Spin-dependent optical calculations indicate that the maximum reflection and absorption for 2D Co2Se3 are in the energy ranges of 0-1 and 12-8 eV, respectively, so this structure is a suitable wave reflector in the infrared range (IR) and a good absorbent in the far-ultraviolet (FUV) range. On the other hand, the unique feature of Co2Se3 encouraged us to study the spin-dependent transport properties. A spin-down current as large as 27(30) µA passing through in the x(y)-direction, while the spin-up current passing through the scattering region up to 1.2 (1) V is approximately zero, induces 100% spin filtering properties in the Co2Se3 monolayer, so this structure has great potential for application in spintronic nano-devices.

Influence of population and radius of cavity bubbles on size of sodium chloride crystals in ultrasound ablation.

Crystal size distribution as a function of power in ultrasound ablation is simulated by using a theoretical method based on population and radius of bubbles. In this method, population and radius of bubbles are related to ultrasound power and Debye temperature of crystals. The best power for production of crystals with uniform size is obtained from the theory. In addition, it is shown that the population of bubbles effects the radius of the productions and the radius of bubbles influences the population of products. Results from the theory are supported by experimental results.