Enhanced thermoelectric efficiency in ferromagnetic silicene nanoribbons terminated with hydrogen atoms

Abstract

Using ab initio methods we calculate thermoelectric and spin thermoelectric properties of silicene nanoribbons with bare, mono-hydrogenated and di-hydrogenated edges. Asymmetric structures, in which one edge is either bare or di-hydrogenated while the other edge is mono-hydrogenated (0H-1H and 2H-1H nanoribbons), have a ferromagnetic ground state and display remarkable conventional and spin thermoelectric properties. Strong enhancement of the thermoelectric efficiency, both conventional and spin ones, results from a very specific band structure of such nanoribbons, where one spin channel is blocked due to an energy gap while the other spin channel is highly conductive. In turn, 0H-2H and 2H-2H nanoribbons (with one edge being either bare or di-hydrogenated and the other edge being di-hydrogenated) are antiferromagnetic in the ground state. Accordingly, the corresponding spin channels are equivalent, and only conventional thermoelectric effects can occur in these nanoribbons.

Thermoelectric properties of zigzag silicene nanoribbons doped with Co impurity atoms

“…Then, the Seebeck coefficient (thermopower) S c and spin Seebeck coefficient (spin thermopower) S s are given by the formulas [5,23] …”

“…For instance, theoretical calculations show that considerable conventional and spin thermopowers can occur in zGNRs with antidotes [21] or in chemically functionalized zSiNRs [22,23]. In this paper we consider the influence of magnetic Co adatoms on transport properties, and especially on spin related thermoelectric phenomena in zSiNRs.…”

Spin effects in thermoelectric phenomena in SiC nanoribbons

“…Indeed, it has been shown that a considerable spin S s and conventional S c thermopowers can be observed in ferromagnetic nanoribbons 15 . The effect can be further enhanced by structural defects like antidots 14 , impurity atoms 25 , or asymmetric hydrogenation of the edge atoms 26 . As a result, the thermoelectric efficiency of such systems can be enhanced in comparison to that in other materials, which makes these structures attractive for applications.…”

Zigzag nanoribbons of two-dimensional silicene-like crystals: magnetic, topological and thermoelectric properties

“…In fact, thermoelectric properties of nanoribbons have been studied theoretically in a couple of papers. [38][39][40][41][42] However, the role of Coulomb interaction and topological edge states in the gap, has not been studied thoroughly enough yet. In a recent paper 43 we have analyzed the influence of topological states on the thermoelectric properties, with the main focus on the role of a staggered exchange field [5][6][7] and of an electric field perpendicular to the atomic plane.…”