Efficiency of Energy Conversion in Thermoelectric Nanojunctions - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




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Abstract: Using first-principles approaches, this study investigated the efficiency ofenergy conversion in nanojunctions, described by the thermoelectric figure ofmerit $ZT$. We obtained the qualitative and quantitative descriptions for thedependence of $ZT$ on temperatures and lengths. A characteristic temperature:$T {0}= \sqrt{\beta-\gammal}$ was observed. When $T\ll T {0}$, $ZT\proptoT^{2}$. When $T\gg T {0}$, $ZT$ tends to a saturation value. The dependence of$ZT$ on the wire length for the metallic atomic chains is opposite to that forthe insulating molecules: for aluminum atomic conducting wires, thesaturation value of $ZT$ increases as the length increases; while foralkanethiol insulating chains, the saturation value of $ZT$ decreases as thelength increases. $ZT$ can also be enhanced by choosing low-elasticity bridgingmaterials or creating poor thermal contacts in nanojunctions. The results ofthis study may be of interest to research attempting to increase the efficiencyof energy conversion in nano thermoelectric devices.



Author: Yu-Shen Liu, Yi-Ren Chen, Yu-Chang Chen

Source: https://arxiv.org/







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