Low-temperature optical absorption and magnetic circular dichroism of YbTe thin films

We have measured the optical absorption and the magnetic circular dichroism (MCD) of a YbTe thin film in the visible and ultraviolet at 300 and 10 °K. The general features of the spectra can be understood in terms of $4f^{14} \left({\mathrm{Yb}}^{2+}\right)\to 4f^{13} 5d(t_{2g}, e_g)$ transitions by neglecting the coupling between a $d$ electron and the $4f^{13}$ core, as in the case of europium chalcogenides. The MCD enables us to identify the diamagnetism of YbTe and to estimate the spectroscopic splitting factor of the lowest excited state. The observation that the first absorption band due to $f\to d$ transition is around 2 eV supports the results of recent pressure-volume studies of YbTe.