Thermoelectric properties of the Al-TM-Si (TM = Mn, Re) 1/1-cubic approximant

<jats:title>ABSTRACT</jats:title><jats:p>The electrical resistivity, thermoelectric power, and thermal conductivity were investigated for the Al<jats:sub>71.6-<jats:italic>x</jats:italic></jats:sub>Mn <jats:sub>17.4</jats:sub>Si<jats:sub><jats:italic>x</jats:italic></jats:sub> and Al<jats:sub>71.6-<jats:italic>x</jats:italic></jats:sub>Re <jats:sub>17.4</jats:sub>Si<jats:sub><jats:italic>x</jats:italic></jats:sub> (7 ≤ <jats:italic>x</jats:italic> ≤ 12) 1/1-cubic approximants. A large thermoelectric power ranging from -40 to 90 μV/K and a low thermal conductivity less than 3 W/K·cm were observed at room temperatures. The electrical resistivity at room temperature for these approximants was kept below 4,000 μΩcm, that is much smaller than that in the corresponding quasicrystals. As a result of the large thermoelectric power, the low thermal conductivity, and the low electrical resistivity, large dimensionless figure of merit <jats:italic>ZT</jats:italic> = 0.10 (<jats:italic>n</jats:italic>-type) and 0.07 (<jats:italic>p</jats:italic>-type) were achieved for the Al<jats:sub>71.6</jats:sub>Re<jats:sub>17.4</jats:sub>Si<jats:sub>11</jats:sub> and Al<jats:sub>71.6</jats:sub>Mn<jats:sub>17.4</jats:sub>Si<jats:sub>11</jats:sub> at room temperature, respectively.</jats:p>