Etude spectrophotometrique de la serie jaune de Cu2O aux basses temperatures

Understanding conductivity in SrCu2O2: stability, geometry and electronic structure of intrinsic defects from first principles

“…The introduction of defects such as copper vacancies and oxygen interstitials leads to less localised holes, with acceptor levels above the valence band maximum. [12][13][14] However, the band gap of Cu 2 O ($2.17 eV 15 ) is too small for transparency preventing its use as a TCO. This problem has been overcome through alloying Cu 2 O with Al 2 O 3 to produce one of the first known p-type TCOs, CuAlO 2 10 which has an optical band gap of 3.5 eV, and preserves the p-type conducting properties of the Cu 2 …”

First-principles study of divalent IIA and transition IIB metals doping into Cu2O

“…It is expected to have an essentially full Cu-3d shell, with a band gap ranging from 2 to 2.2 eV [28,29] , which usually was set to 2. 17 eV [30] . We can fi nd that the band gap calculated by DFT (about 0.5-0.8 eV ) is much smaller than the experimental value (2.17 eV) [31] , attributable to the deficient treatment in the electrical and electronic exchange interaction with GGA [32] , while the Hartree-Fock methods overestimate the band gap (9.7 eV) significantly [33] .…”

Electromagnetic-induced transparency of Wannier-Mott excitons

“…The splitting δ 2P −1S and the coefficient A = |D 20y | 2 /( 0h γ 2P V ) depends on the material parameters, |D 20y | 2 being proportional to the 2P exciton oscillator strength. For the yellow exciton series of bulk Cu 2 O one hashω 2P 2.148 eV andhδ 2P −1S = 115 meV [7], while from the measured linewidthhγ 2P 1 meV [7] and oscillator strength [6] the coefficient A can be estimated to be A 0.02. Such a small value, due to the fact that the 2P exciton line is rather weak (second-class transition) [8], is comparable to that of cold atomic gases where A commonly varies in the range 10 −2 -10 −1 .…”

“…It originates mainly from indirect transitions, surface and impurity scattering and is directly related to the background value κ ∞ of the extinction coefficient. The latter can be estimated from the logarithm of the measured exciton peak transmission relative to the background value; from [6] we can infer an average value κ ∞ 4 × 10 −4 over the 2P exciton absorption linewidth yielding ∞ = 2 × 10 −3 . With the help of (9) we evaluate G T which we show in fig.…”

“…We specifically consider the "yellow exciton" series in Cu 2 O for which a Λ-type model Hamiltonian will be developed. The reason for such a choice is two-fold, namely, all the spectroscopic parameters are well known [6] and the relevant pump and probe set-up required for the demonstration of electromagnetic-induced transparency has already been employed to investigate the optical Stark effect in Cu 2 O [7].c EDP Sciences …”