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We present experimental studies of the magnetization of electrons in semiconductorquantum dots. Starting from a modulation-doped AlGaAs/GaAs heterostructure an array of dots was patterned by laser-interference lithography and deep mesa etching. The quantum-dot array was integrated into a highly sensitive micromechanical cantilever magnetometer. At a temperature of 0.3 K we observe pronounced oscillations in the magnetization. With regard to their periodicity and temperature dependence they differ from the de Haas–van Alphen effect observed in a two-dimensional electron system. We find that the magnetization calculated from the single-particle Fock–Darwin energies of a quantum dot does not reproduce the experiment. From this we conclude that the electronic ground state of the dots is strongly influenced by electron–electron interaction.
Tobias Kippenberg, Rui Ning Wang, Guanhao Huang, Yujia Yang, Junqiu Liu, Arslan Sajid Raja, Jiahe Pan
Thorsten Schmitt, Vladimir N. Strocov, Xingye Lu, Sophie Beck