The electronic structures of various Cu^(+) luminescence centers in wurtzite ZnS are studied by using first-principles linear muffin-tin-orbital method combining atomic sphere approximation.The results for ZnS:Cu:Cl a...The electronic structures of various Cu^(+) luminescence centers in wurtzite ZnS are studied by using first-principles linear muffin-tin-orbital method combining atomic sphere approximation.The results for ZnS:Cu:Cl and ZnS:Cu:Al show that Cu acceptor states are anomalously deep(beyond 2.7eV above the top of valence band)and located near the bottom of conduction band in these two cases.On the other hand,the results for ZnS:Cu with sulfur vacancies manifest that the Cu+center is an associated center,whose Cu d-like states are situated above the top of valence band.展开更多
By using LMTO-ASA method and supercell approach,the self-consistent band structures forα-Ti,ε-Ti_(2)N,andδ-TiN have been calculated.Moreover,α-Ti,ε-Ti_(2)N,andδ-TiN were taken as three samples corresponding to T...By using LMTO-ASA method and supercell approach,the self-consistent band structures forα-Ti,ε-Ti_(2)N,andδ-TiN have been calculated.Moreover,α-Ti,ε-Ti_(2)N,andδ-TiN were taken as three samples corresponding to TiNx films for x=0,0.5,1.0.Then,according to the phase diagram of Ti-N and statistical supercell method,we have,for the first time to our knowledge,calculated the electronic structures of equilibrium-state TiN_(x) films for all compositions of x<1.0.展开更多
文摘The electronic structures of various Cu^(+) luminescence centers in wurtzite ZnS are studied by using first-principles linear muffin-tin-orbital method combining atomic sphere approximation.The results for ZnS:Cu:Cl and ZnS:Cu:Al show that Cu acceptor states are anomalously deep(beyond 2.7eV above the top of valence band)and located near the bottom of conduction band in these two cases.On the other hand,the results for ZnS:Cu with sulfur vacancies manifest that the Cu+center is an associated center,whose Cu d-like states are situated above the top of valence band.
文摘By using LMTO-ASA method and supercell approach,the self-consistent band structures forα-Ti,ε-Ti_(2)N,andδ-TiN have been calculated.Moreover,α-Ti,ε-Ti_(2)N,andδ-TiN were taken as three samples corresponding to TiNx films for x=0,0.5,1.0.Then,according to the phase diagram of Ti-N and statistical supercell method,we have,for the first time to our knowledge,calculated the electronic structures of equilibrium-state TiN_(x) films for all compositions of x<1.0.
