Thermal conductivity of Bi2Te3 tilted nanowires, a molecular dynamics study

S Li and L Chaput and N Stein and C Frantz and D Lacroix and K Termentzidis, APPLIED PHYSICS LETTERS, 106, 233108 (2015).

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 0.34W/m K, significantly reduced compared to nanowire along the 010 direction (0.59W/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 5.3nm 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. (C) 2015 AIP Publishing LLC.

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