De Haas–van Alphen effect
The de Haas–van Alphen effect, often abbreviated to dHvA, is a quantum mechanical effect in which the magnetic moment of a pure metal crystal oscillates as the intensity of an applied magnetic field B is increased. Other quantities also oscillate, such as the resistivity (Shubnikov–de Haas effect), specific heat, and sound attenuation and speed. It was discovered in 1930 by Wander Johannes de Haas and his student Pieter M. van Alphen.
The period, when plotted against , is inversely proportional to the area of the extremal orbit of the Fermi surface, in the direction of the applied field.
where S is the area of the Fermi surface normal to the direction of B.
Even when the de Haas-van Alphen effect was predicted theoretically by Lev Landau in 1930, he discarded it as it thought that the magnetic fields necessary for its demonstration could not be created in a laboratory yet. The effect is described mathematically using Landau quantization of electron energy in an applied magnetic field. A strong magnetic field — typically several teslas — and a low temperature are required to cause a material to exhibit the dHvA effect.
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