Observation of giant magnetoresistance oscillations in the high-$T_c$ phase of the two-dimensional organic conductor β-(BEDT-TTF${)}_2$${\mathrm{I}}_3$

Giant Shubnikov–de Haas oscillations have been observed in the high-$T_c$ phase (${\beta }_H$) of an organic conductor β-(BEDT-TTF${)}_2$ ${\mathrm{I}}_3$. The frequency of the oscillations ($H_0$=3730T) Corresponds to about one carrier per unit cell. The extraordinary large amplitude of the magnetoresistance oscillations has been attributed to the two-dimensional nature of the cylindrical Fermi surface exhibiting only a small warping along the direction of lowest conductivity.