Thermoelectric properties of a ferromagnet-superconductor hybrid junction: Role of interfacial Rashba spin-orbit interaction

Abstract

We investigate thermoelectric properties of a ferromagnet-superconductor hybrid structure with Rashba spin-orbit interaction and delta function potential barrier at the interfacial layer. The exponential rise of thermal conductance with temperature manifests a cross-over temperature scale separating two opposite behaviors of it with the change of polarization in the ferromagnet whereas the inclusion of interfacial Rashba spin-orbit field results in a non-monotonic behavior of it with the strength of Rashba field. We employ scattering matrix approach to determine the amplitudes of all the scattering processes possible at the interface to explain the thermoelectric properties of the device. We examine Seebeck effect and show that higher thermopower can be achieved when the polarization of the ferromagnet tends towards the half-metallic limit. It can be enhanced even for lower polarization in presence of the finite potential barrier. In presence of interfacial Rashba spinorbit interaction, Seebeck coefficient rises with the increase of barrier strength and polarization at weak or moderate interfacial Rashba field. From the application perspective, we compute the figure of merit and show that zT ∼ 4 − 5 with higher polarization of the ferromagnet both in absence and presence of weak or moderate Rashba spin-orbit interaction along with the scalar potential barrier.

Spin-flip enhanced thermoelectricity in superconductor-ferromagnet bilayers

“…Following this principle, large spin-dependent TE effects have been theoretically proposed [2][3][4][5][6][7][8][9] and experimentally demonstrated [10][11][12] in spin-split and -polarized superconducting tunnel contacts [13]. Furthermore, TE properties in a variety of systems have been investigated [14][15][16]. In most of the cases, the Zeeman-split superconducting heterostructures exhibiting sizeable TE effects require a large externally applied magnetic field [10,17].…”

Thermoelectricity carried by proximity-induced odd-frequency pairing in ferromagnet/superconductor junctions

“…which are obtained by diagonalizing Eq. (4) [38]. Turning to the SC region (z < 0), the solution is instead given by [70] SC…”

“…(19) and (22). Note that the effect of the interfacial RSOI enters through the boundary condition [38].…”

“…Recently, the idea of implementing spin-splitting through FM/SC structures has been shown to yield considerable enhancement of the thermoelectricity [29][30][31][35][36][37][38][39][40]. Such enhancement of the thermoelectricity is always useful due to the prospects of application [41][42][43][44].…”

Thermoelectric transport coefficients of quark matter

“…A measure of the electric field produced in a conducting medium due to a temperature gradient is the Seebeck coefficient which is defined as the ratio of an electric field to the temperature gradient in the limit of vanishing electric current. Seebeck effect has been extensively studied in condensed matter systems such as superconductors, quantum dots, hightemperature cuprates, superconductor-ferromagnetic tunnel junctions, low dimensional organic metals, etc [64][65][66][67][68][69][70][71][72]. Such a phenomenon could also be present in the thermal medium created in heavy-ion collisions.…”