Thermal conductivity of Bi2Te3 tilted nanowires, a molecular dynamics study

• Published in: Applied physics letters 2015-06, Vol.106 (23)
• Main Authors: Shen, Li, Chaput, Laurent, Stein, Nicolas, Frantz Cedric, Lacroix, David, Termentzidis Konstantinos
• Format: Article
• Language: English
• Subjects: Anisotropy; Applied physics; Bismuth tellurides; Chemical Sciences; Condensed Matter; Dynamic stability; Dynamic structural analysis; Engineering Sciences; Heat conductivity; Heat transfer; Material chemistry; Materials Science; Mechanics; Micro and nanotechnologies; Microelectronics; Molecular dynamics; Nanowires; Physics; Size effects; Structural analysis; Structural stability; Thermal conductivity; Thermics; Thermoelectric materials
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4922480

Evidence for an excellent compromise between structural stability and low thermal conductivity has been achieved with tilted Bi2Te3 nanowires. The latter ones were recently fabricated and there is a need in modeling and characterization. The structural stability and the thermal conductivity of Bi2Te3 nanowires along the tilted [015]* direction and along the [010] direction have been explored. For the two configurations of nanowires, the effect of the length and the cross section on the thermal conductivity is discussed. The thermal conductivity of infinite size tilted nanowire is 0.34 W/m K, significantly reduced compared to nanowire along the [010] direction (0.59 W/m K). This reveals that in Bi2Te3 nanowires the structural anisotropy can be as important as size effects to reduce the thermal conductivity. The main reason is the reduction of the phonon mean free path which is found to be 1.7 nm in the tilted nanowires, compared to 5.3 nm for the nanowires along the [010] direction. The fact that tilted Bi2Te3 nanowire is mechanically stable and it has extremely low thermal conductivity suggests these nanowires as a promising material for future thermoelectric generation application.