Effects of charging and electric field on the properties of silicene and germanene

Using first-principles Density Functional Theory calculations, we showed that electronic and magnetic properties of bare and Ti adatom adsorbed single-layer silicene and germanene, which are charged or exerted by a perpendicular electric field are modified to attain new functionalities. In particular, when exerted by a perpendicular electric field, the symmetry between the planes of buckled atoms is broken to open a gap at the Dirac points. The occupation of 3d-orbitals of adsorbed Ti atom changes with charging or applied electric field to induce significant changes of magnetic moment. We predict that neutral silicene uniformly covered by Ti atoms becomes a half-metal at a specific value of coverage and hence allows the transport of electrons in one spin direction, but blocks the opposite direction. These calculated properties, however exhibit a dependence on the size of the vacuum spacing between periodically repeating silicene and germanene layers, if they are treated using plane wave basis set within periodic boundary condition. We clarified the cause of this spurious dependence and show that it can be eliminated by the use of local orbital basis set.Comment: Accepted for Journal of Physics: Condensed Matte

A Review on Non-Newtonian Nanofluid Applications for Convection in Cavities under Magnetic Field

This review is about non-Newtonian nanofluid applications for convection in cavities under a magnetic field. Convection in cavities is an important topic in thermal energy system, and diverse applications exist in processes such as drying, chemical processing, electronic cooling, air conditioning, removal of contaminates, power generation and many others. Some problems occur in symmetrical phenomena, while they can be applicable to applied mathematics, physics and thermal engineering systems. First, brief information about nanofluids and non-Newtonian fluids is given. Then, non-Newtonian nanofluids and aspects of rheology of non-Newtonian fluids are presented. The thermal conductivity/viscosity of nanofluids and hybrid nanofluids are discussed. Applications of non-Newtonian nanofluids with magnetohydrodynamic effects are given. Different applications of various vented cavities are discussed under combined effects of using nanofluid and magnetic field for Newtonian and non-Newtonian nanofluids. The gap in the present literature and future trends are discussed. The results summarized here will be beneficial for efficient design and thermal optimization of vented cavity systems used in diverse energy system applications