Binding energy of negative trions at high magnetic fields in a CdTe quantum well

We present results of numerical calculations of electronic states of an exciton and a trion in a CdTe quantum well at magnetic fields up to 150T. The exciton state and the trion states were computed using a variational procedure. We estimated the binding energy of the trion in a singlet state with the z-component of angular momentum L_z=0, as well as the binding energy of the trion in a triplet state with L_z=-1. Recent experimental results show that even up to 44T the binding energy of negative trion in a singlet state is bigger than in a triplet state. We show that at a critical field B_c=65T the two binding energies cross and above B_c the binding energy of the trion in a triplet state is bigger than in the singlet state.