Phase Separation in the Semiconducting Binary Liquid Selenium-Thallium

We report the first detailed study of phase separation in a semiconducting binary liquid (Se-T1). We have studied both the electrical conductivity σ and the location of the miscibility gap in the concentration-temperature ($x-T$) plane. Even though the conductivity varies by 3 to 4 orders of magnitude in the transition region, it is found that (i) the law of rectilinear diameters holds with high precision, (ii) the critical exponent ${\beta }_x$ for the $x-T$ phase boundary agrees to within experimental accuracy with ${\beta }_{\sigma }$ for the $\sigma -T$ phase boundary, and (iii) $\beta =0.348\mathrm{}\pm 0.015$.