Effects of uniaxial stress on excitons in Cu 2 O

摘要: We have investigated the effects of uniaxial stress up to 2.5 kbar on first four dipole-forbidden states yellow exciton series in cuprous oxide. The linear and nonlinear splittings shifts as well symmetries stress-split components were determined using quadrupole-dipole Raman-scattering technique involving odd-parity phonons. observed triply degenerate $1S$ quadrupole state split into a singlet doublet with energy increasing decreasing seen by Gross Kaplyanskii. For higher $S$ states, however, sense splitting was reversed from that $1S$, while magnitude $3S$ exceeded previously noted Agekyan Stepanov. quadratic coefficients for all $3D$, $4S$ found be equal those markedly different. A theoretical analysis carried out [001] effective-Hamiltonian formalism including both deformation bands electron-hole exchange. theory accounts satisfactorily general features only if sign exchange constant are considered dependent state. $3S$, dependence cannot reconciled excitons. These results suggest "$3S$ exciton" may actually belong green-exciton series, or interactions between green excitons different principal quantum numbers significant although not included theory.