Quantum thermopower oscillations in Al-Ga dilute alloys
Sergey E Demyanov, Alexander A Drozd, Alexander V Petrov
The change in the Fermi surface of aluminium caused by alloying with gallium was studied by the method of quantum thermopower oscillations under magnetic breakdown effect conditions. Two frequencies of the thermopower oscillations were observed. The first one corresponds to the cross-section of the b orbit, which is associated with a hole sheet of the Fermi surface in the second Brillouin zone. The second one, the e frequency, is modulated by the bfrequency. Its appearance shows the coherent nature of magnetic breakdown, which is not violated by a relatively large quantity of impurity. The e frequency corresponds to a combined electron orbit, which is formed in the second and third Brillouin zones as a result of the magnetic breakdown effect. The experimental results demonstrate that alloying with gallium leads to a decrease of volume of the electron part of the aluminium Fermi surface, at least in the region of the W symmetry point of the Brillouin zone.