Excitons in monoclinic zinc diphosphide: The A-exciton series and Fano effect

Excitonic Polaritons in ZnAs2

“…[1][2][3] In the optical spectra of the ZnP 2 crystals near the fundamental absorption region, a hydrogen-like series C of the electricdipole exciton and three relatively poor dipole-forbidden exciton hydrogen-like series are revealed. [11][12][13][14][15][16] In the C 5 2h symmetry group, wich consists of the ZnAs 2 and ZnP 2 bindings, a singlet exciton of the À À 2 ðzÞ symmetry allowed for E k c polarization is present. For E ?…”

“…Such a difference is revealed for ZnAs 2 crystals and corresponds to the excitonic states of crystal with C 5 2h symmetry. [14][15][16] The lines n ¼ 2 (1.0486 eV) and n ¼ 3 (1.0504 eV) and in the short-wavelength region, n ¼ 1 (1.0392 eV) for E ? c polarization are also revealed.…”

“…c polarization, a B hydrogen-like series is revealed. According to the selection rules, [14][15][16] a B series can be formed by the states of the 2À À 1 þ À À 2 ortoexciton symmetry. These states are forbidden in the electrical quadruple approximation.…”

“…The exciton A series for ZnP 2 is conditioned by the partially allowed dipole transitions of the nS states of the À À 2 ðxÞ orthoexciton symmetry split also by the changing interaction conditioned by the mixing of the spin-orbit interaction with the À À 2 ðzÞ state. [14][15][16] The maximum of the basic orthoexciton B state for ZnAs 2 is 1:0 AE 0:2 meV from the maximum of the transverse singlet exciton basic state (! t ) of the À À 2 ðzÞ symmetry.…”