Hole spin anisotropy in single Mn-doped quantum dots

Abstract

The anisotropy in the exchange interaction between a single magnetic atom and a single exciton confined in a quantum dot (QD) is revealed experimentally. In a transverse magnetic field we directly observe the orientation of the magnetic ion spin along the resultant direction of the external magnetic field and the hole exchange field. With an increasing transverse magnetic field, this orientation progressively cancels the exchange interaction with the hole and at a high field the fine structure is mainly controlled by the electron-Mn coupling. At intermediate fields, we observe emission replicas caused by multiple spin flips within the Zeeman split ground state of a single Mn. All these features are well modeled by the magnetic field dependence of the stationary states of a single Mn spin in the exchange field of a heavy-hole exciton.