Resonant tunneling and magnetism in erbium arsenide semimetal quantum wells

Resonant tunneling through confined states in a semimetallic, magnetic quantum well has been observed and investigated for the first time. The results reported here firmly establish magnetization controlled quantum transport and the potential of integrating epitaxial layers of magnetic and metallic materials with compound semi-conductors for electronic, photonic and spintronic devices.; Quantum confinement and the effect of magnetization in ErAs quantum wells are investigated by transport measurements through the GaAs/AlAs/ErAs resonant tunneling diodes (RTDs). Reliable selective contact to the nanometer epitaxial ErAs films has enabled fabrication and measurement of three terminal structures. Measurement of the quantum well voltage in RTDs under bias has been used to determine the energy of the confined electronic states in the high quality semimetal film. Using the thickness dependence of the voltage for resonant tunneling, we have mapped the light and heavy hole states along the [113] direction. Magnetic field dependence distinguishes the two different resonant channels which we identify as the mJ = +/-1/2 light hole and mJ = +/-3/2 heavy hole bands in ErAs. The light hole shows a splitting which is anisotropic with applied field direction and the heavy hole shows anisotropy in field dependent strength, but no splitting. The symmetry of the anisotropy is shown to reflect the strain on the ErAs film which modifies the crystal field experienced by the Er 4f localized moments.