SearcharxivSearch

arXiv subjects

M. Esmaeilzadeh

Publications and source records attributed to M. Esmaeilzadeh.

2 recordsLinked to original sources

High-Efficiency spin-Seebeck Diode in an $α'$-Borophene FM/Normal/FM Nanoribbon Junction

The $α'$-borophene nanoribbon ($α'$-BNR), due to its incredible properties such as high stability and great mobility of carriers, demonstrates high efficiency in thermoelectric devices. We show that these properties enable us to produce a pure spin current by applying a temperature gradient with lower energy consumption in a ferromagnetic/normal/ferromagnetic (FM/Normal/FM) junction. Spin-dependent thermoelectric properties and spin-Seebeck are studied in this junction using the tight-binding (TB) formalism in combination with the non-equilibrium Green's function method (NEGF). The pure spin current due to the breaking of the electron-hole symmetry is induced in the system so that it can act as a spin-Seebeck diode. Moreover, the negative differential spin-Seebeck effect can be observed in the system. Finally, we show that, under the same conditions, the $α'$-BNR has a much higher power factor compared to that of graphene and silicene, which is due to the high asymmetry between the electrons and holes in the $α'$-BNR. The exceptional features of $α'$-BNR make it a very suitable choice for thermoelectric devices.

cond-mat.mes-hall

Perfect valley polarization in MoS2

We study perfect valley polarization in a molybdenum disulfide MoS2 nanoribbon monolayer using two bands Hamiltonian model and non-equilibrium Green's function method. The device consists of a one-dimensional quantum wire of MoS2 monolayer sandwiched between two zigzag MoS2 nanoribbons such that the sites A and B of the honeycomb lattice are constructed by the molecular orbital of Mo atoms, only. Spin-valley coupling is seen in energy dispersion curve due to the inversion asymmetry and time-reversal symmetry. Although, the time reversal symmetry is broken by applying an external magnetic field, the valley polarization is very small. A valley polarization equal to 46% can be achieved using an exchange field of 0.13 eV. It is shown that a particular spin-valley combination with perfect valley polarization can be selected based on a given set of exchange field and gate voltage as input parameters. Therefore, the valley polarization can be detected by detecting the spin degree of freedom.

cond-mat.mes-hall