Spin caloritronics in a chiral double-strand-DNA-based hybrid junction

Abstract

The chiral-induced spin selectivity effect is of fundamental importance in further understanding the thermospin transport in double-strand-DNA (dsDNA) molecules. Here we propose a hybrid dsDNA-based thermoelectric device made of a chiral dsDNA molecule coupled to normal-metal and superconducting leads for exploring the spin-dependent thermoelectricity. We give a comparison of the thermoelectric responses of the dsDNA system and the quantum dot system in the presence of superconductivity, and find that the former does not rely on external means to break the particle-hole symmetry due to the intrinsic properties of dsDNA molecules. Our findings show that spin-thermoelectric coefficients can go beyond charge thermoelectric ones, and even a pure spin thermopower can be generated by adjusting the external magnetic field and the temperature, which indicates that this chiral dsDNA hybrid junction can in practice act as a pure spin-current generator. Furthermore, the sizable spin and charge thermoelectric conversion efficiencies can be achieved by tuning system parameters. Our results open opportunities for fabricating spin caloritronic devices based on chiral molecules.