Impact of heavy hole–light hole coupling on the exciton fine structure in quantum dots

We present analytical results which describe the properties of the exciton ground state in a single semiconductor quantum dot (QD). Calculations are performed within the Luttinger–Kohn and Bir–Pikus Hamiltonian theory. We show in an explicit form that an interplay of the exchange interaction and the heavy hole–light hole coupling, which is due to the in-plane asymmetries of the dot shape and the strain distribution, plays an essential role. For both the bright and dark exciton, this combined effect leads to a dependence of the fine structure splitting and polarizations on the main anisotropy axis direction relative to the dot orientation. Basing on the obtained analytical expressions, we discuss some special cases in details.