title: Atomic layer-by-layer thermoelectric conversion in topological insulator bismuth/antimony tellurides.
abstract: Material design for direct heat-to-electricity conversion with substantial efficiency essentially requires cooperative control of electrical and thermal transport. Bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3), displaying the highest thermoelectric power at room temperature, are also known as topological insulators (TIs) whose electronic structures are modified by electronic confinements and strong spin-orbit interaction in a-few-monolayers thickness regime, thus possibly providing another degree of freedom for electron and phonon transport at surfaces. Here, we explore novel thermoelectric conversion in the atomic monolayer steps of a-few-layer topological insulating Bi2Te3 (n-type) and Sb2Te3 (p-type). Specifically, by scanning photoinduced thermoelectric current imaging at the monolayer steps, we show that efficient thermoelectric conversion is accomplished by optothermal motion of hot electrons (Bi2Te3) and holes (Sb2Te3) through 2D subbands and topologically protected surface states in a geometrically deterministic manner. Our discovery suggests that the thermoelectric conversion can be interiorly achieved at the atomic steps of a homogeneous medium by direct exploiting of quantum nature of TIs, thus providing a new design rule for the compact thermoelectric circuitry at the ultimate size limit.
authors.affiliation: Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang University of Science and Technology (POSTECH) , 77 Cheongam-Ro, Pohang 790-784, Korea.
authors.forename: Ji Ho
authors.initials: JH
authors.lastname: Sung
authors.forename: Hoseok
authors.initials: H
authors.lastname: Heo
authors.forename: Inchan
authors.initials: I
authors.lastname: Hwang
authors.forename: Myungsoo
authors.initials: M
authors.lastname: Lim
authors.forename: Donghun
authors.initials: D
authors.lastname: Lee
authors.forename: Kibum
authors.initials: K
authors.lastname: Kang
authors.forename: Hee Cheul
authors.initials: HC
authors.lastname: Choi
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Park
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Jhi
authors.forename: Moon-Ho
authors.initials: MH
authors.lastname: Jo