Magnetic field dependence of hole levels in InAs quantum dots

We have studied the charging of InAs quantum dots with holes in perpendicular fields up to 16 T by capacitance—voltage spectroscopy. The first two charging peaks show almost no shift with magnetic field which is consistent with the filling of a twofold degenerate s-like state with no orbital angular momentum. The next four charging peaks shift towards lower and higher energy in an alternating fashion. Peaks 5 and 6 shift approximately twice as strong as peaks 3 and 4. This behavior cannot be explained by the charging of a fourfold degenerate p-shell according to Hund′s first rule. We speculate that the p-shell is not completely filled before the filling of the d-shell starts.