Landau Level Broadening of the Electrons in Antimony

The Landau level broadening of the electrons in antimony has been investigated by ultrasonic attenuation measurements under the conditions q // H // a bisectrix axis, ν=60 MHz (quasi-longitudinal waves), 1.15 K< T <1.90 K and H<120 kG. From the Shubnikov-de Haas type oscillations in 3.5 kG\({\lesssim}H{\lesssim}7\) kG for an annealed sample, an effective Dingle temperature T _D =0.42 K is obtained for the electrons, while from the giant quantum attenuation in high fields up to 120 kG an effective temperature of the level broadening, T _g =0.0027 K, is obtained for the same extremal orbit of the electrons and for the same sample. It is shown that T _D is sensitive to whether samples were heat-treated or not, but T _g is rather insensitive. The origin of the extraordinarily large difference between T _D and T _g is discussed in some detail.