Solution growth and low-temperature thermoelectric properties of single crystalline β-FeSi2

We have measured the Seebeck coefficient and power factor of single crystalline beta-FeSi₂ grown by a temperature gradient solution growth (TGSG) method using Ga and Zn solvent. Typical resistivity and carrier density at 300 K were 0.03 Omegacm and 2times10¹⁹ cm^-3 for p-type and 0.2 Omegacm and 5times10¹⁸ cm^-3 for n-type crystals, respectively. The Seebeck coefficient measured along [011] direction was approximately 350 muV/K(p-type) and -700 mu;V/K(n-type) at 300 K and showed a maximum value of 500 mu;V/K(p-type, T=~25 K) and 2100 mu;V/K(n-type, T=~70 K). The maximum power factor was 4.2 times 10^-6 Wcm^-1K^-2 (p-type, T=170 K) and 23 times 10^-6 Wcm^-1K^-2 (n-type, T=100 K). The value was more than one order of magnitude larger than that of previously reported.