Electron–electron interaction in p-SiGe/Ge quantum wells

The temperature dependent magnetoresistance of high mobility p-SiGe/Ge quantum wells is studied with hole densities ranging from 1.7 to 5.9 × 10 11 cm −2. At magnetic fields below the onset of quantum oscillations that reflect the high mobility values (up to 75000 cm 2/Vs), we observe the clear signatures of electron–electron interaction. We compare our experiment with the theory of electron–electron interaction including the Zeeman band splitting. The observed magnetoresistance is well explained as a superposition of band structure induced positive magnetoresistance and the negative magntoresistance due to the electron–electron interaction effect.