Some physical properties of ReSi1.75 single crystals

We investigated the electronic transport properties and the magnetic susceptibility of the semiconducting silicide ReSi1.75. This compound crystallises in a monoclinic structure (space group P1). The resistivity of this silicide is anisotropic depending on the direction of the current flow. At high temperatures we observe thermally activated behaviour for the resistivity with one (or two) energy gap(s) Eg = 0.16 eV (0.30 eV). Hall effect measurements yield a positive Hall coefficient in the temperature range between 30 and 660 K. At room temperature we found a Hall carrier concentration of 3.7 × 1018 cm−3 and a quite high Hall mobility of 370 cm2/V · s. As the resistivity, the magnetic susceptibility of ReSi1.75 is anisotropic depending on the orientation of the magnetic field relative to the crystallographic axes. At room temperature χ is strongly diamagnetic. Below about 50 K, χ increases with decreasing temperature.