The de Haas-van Alphen effect in nanostructures of cadmium fluoride

Measurements of the field and temperature dependences of static magnetic susceptibility demonstrate de Haas-van Alphen oscillations at high temperatures and low magnetic fields in sandwich nanostructures, which are represented by an ultranarrow $p$-type CdF$_2$ quantum well confined by $\delta$ barriers heavily doped with boron on the surface of an $n$-type CdF$_2$ crystal. The temperature dependences of the de Haasvan Alphen oscillation amplitudes indicate a small value of the effective mass of two-dimensional holes, as a result of which, the strong field assumption, $\mu B\gg$ 1, is fulfilled at high temperatures. It is for the first time that a periodic variation in the de Haas-van Alphen oscillation frequency is detected and is accompanied by a diamagnetic response as temperature is increased. This phenomenon manifests itself as synchronous temperature oscillations of the density and effective mass of two-dimensional holes as a result of the mesoscopic properties of $\delta$ barriers.