Year: 2012
Type: article
Abstract: Recently, we reported [M. Wagner et al., J. Mater. Res. 26, 1886 (2011)] transport measurements on the semiconducting intermetallic system RuIn${}_{3}$ and its substitution derivatives RuIn${}_{3\ensuremath{-}x}{A}_{x}$ ($A=\text{Sn,}\phantom{\rule{4.pt}{0ex}}\text{Zn}$). Higher values of the thermoelectric figure of merit ($zT=0.45$) compared to the parent compound were achieved by chemical substitution. Here, using density functional theory based calculations, we report on the microscopic picture behind the measured phenomenon. We show in detail that the electronic structure of the substitution variants of the intermetallic system RuIn${}_{3\ensuremath{-}x}{A}_{x}$ ($A=\text{Sn,}\phantom{\rule{4.pt}{0ex}}\text{Zn}$) changes in a rigid-band-like fashion. This behavior makes possible the fine tuning of the substitution concentration to take advantage of the sharp peaklike features in the density of states of the semiconducting parent compound. Trends in the transport properties calculated using the semiclassical Boltzmann transport equations within the constant scattering time approximation are in good agreement with the former experimental results for RuIn${}_{3\ensuremath{-}x}$Sn${}_{x}$. Based on the calculated thermopower for the $p$-doped systems, we reinvestigated the Zn-substituted derivative and obtained ZnO-free RuIn${}_{3\ensuremath{-}x}$Zn${}_{x}$. The new experimental results are consistent with the calculated trend in thermopower and yield a large $zT$ value of 0.8.
Source: Physical Review B
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funder: Deutsche Forschungsgemeinschaft
Award: G757383574
OpenAlex ID: W2507316136