Shubnikov-de Haas effect study of cylindrical Fermi surfaces in UAs₂

Shubnikav-de Haas effect measurements were performed on a high-quality whisker single crystal of UAs₂. Complementary electrical resistivity and specific heat experiments were also carried out. Five of the seven detected branches exhibit angular dependences clearly indicating cylindrical Fermi surfaces. The effective cyclotron masses were determined to range from 0.33 to 4.5 _mo, which yielded an electronic specific heat coefficient of 10 mj K^-2 mol^-1. This is in very good agreement with the value 11.7 mJ K^-2 mol^-1 determined directly by the low-temperature specific heat measurement. The two-dimensional Fermi surfaces are formed in a strongly flattened magnetic Brillouin zone and the conduction electrons are confined mainly in the U planes, indicating an important contribution of itinerant 5f electrons.