Thermoelectric and ferroelectric properties of metal chalcogenides/ Oxy-chalcogenides and topological quantum materials

Abstract

Heat dissipation being a natural by-product of every form of utilized energy, thermoelectrics (TE) constitute a viable means of efficient energy management in near future, by converting the untapped heat into electrical energy On the other hand, the discovery of topological quantum materials (TQM) (e.g. topological insulator, topological crystalline insulator, topological semimetal) with unique metallic surface states has added a new dimension in the field of electronics and spintronics. Interestingly, most of the TQM are also good candidates for TE because both demand similar material features such as heavy constituent elements, narrow band gap, and strong spin-orbit coupling. Ferroelectrics, a vital branch of functional materials with spontaneous switchable electric polarization, are one of the most studied system due to their wide range of applications including TE. Presence of ferroelectric instability in TE materials such as in GeTe are proven to be beneficial in lowering their lattice thermal conductivity and hence tuning their TE performance. Recently, various metal chalcogenides/oxy-chalcogenides are getting attention as potential candidates for 2D-ferroelectrics which are much coveted system due to their broad use in nanodevices. In a nut-shell metal chalcogenides/oxy-chalcogenides present a common platform for exploring thermoelectrics, quantum materials and ferroelectrics. This chapter highlights a brief introduction to (a) thermoelectrics and its recent advances, (b) thermoelectric materials of interest for the thesis, (c) topological quantum materials and its correlation with thermoelectrics and (d) ferroelectricity. In the last part of this chapter is focused on a general discussion of synthesis, characterizations and thermoelectric measurements of metal chalcogenide/oxy-chalcogenides.