We report first principles calculations on the magnetism and electronic structures for nitrogen-doped anatase TiO2 (N:TiO2). Our calculations indicate that magnetic state is the ground state for N:TiO2 systems. An isolated N atom produces a total magnetic moment of 1.00μB and introduces spin-polarized 2p states in the band gap. The origin of the magnetic moments is the holes in N 2p π band of the N dopant. Several doping configurations studied suggest the existence of ferromagnetic coupling between N dopants. The ferromagnetism in N:TiO2 can be attributed to the hole-mediated double exchange through the strong p-p interaction between N and O.

Improvement of the photocatalytic properties of TiO2 by (Fe+Mo) co-doping-A possible way to retard the recombination processResearch on the effect of crystal structures on W-TiO2 nanotube array photoelectrodes by theoretical and experimental methodsInterface electronic behavior of two-dimensional large scale MoS 2 /TiO 2 hetero-thin films has been studied using photoemission spectroscopy. We show a clear experimental evidence for type II band alignment and upward band bending ($0.55 eV) at the interface of this system. The valence band offset at monolayer MoS 2 /TiO 2 interface was measured to be 2.15 eV, while the conduction band offset was 1.00 eV. The unique interface band positions introduce a strong build-in electric field for efficient electron-hole separation. In addition, thermal treatment results in better interfacial coupling and charge separation efficiency thus enhanced visible light photoactivity. Our results explicate the mechanism and emphasize its huge potential in visible light photocatalysis. V C 2015 AIP Publishing LLC. [http://dx.

We report stable room temperature ferromagnetism in nitrogen doped In2O3 (N–In2O3) based on density functional theory. Our investigation on the electronic and magnetic properties of N–In2O3 suggests that N dopant introduces spin-polarized hole states in the band gap generating a total magnetic moment of 1.0μB per N, which is mainly localized on the doped N atoms. The ferromagnetic interaction in N–In2O3 system is mainly driven by the occurrence of coupling chains between a first N (N1)-2p to a second N (N2)-2p via a bridging In 5p and 4d orbitals.

InSe based Janus structures has been investigated. The obtained results 6 suggest that the In 2 SeTe Janus structure has an intrinsic direct band gap 7 which is beneficial for optoelectronic applications. The direct band gap nature 8 of In 2 SeTe Janus structure is due to the strong coupling of p z orbitals 9 between the Se and Te sublayers, which emphasizes the importance of the 10 intra-layer interactions. In addition, the effective mass of the holes in In 2 SeTe 11 is one order of magnitude smaller than that of intrinsic InSe monolayer, 12 which makes it a good candidate for p-type semiconductor. The broken 13 mirror symmetry of the Janus structures induces out-of-plane dipolar 14 polarization, yielding additional built-in electric field and offering extra 15 channel to tune its electronic band structure. The electric field has dominated 16 effluences on the charge polarization on anions thus exhibiting stronger band 17 tunability on the valence bands. These results indicate that the preparation of 18 In 2 SeTe Janus structure provides a new way for the future use of two-19 dimensional materials in optoelectronic nanodevices.

Using In2O3 as a host matrix, extensive calculations based on density functional theory have been carried out to understand the electronic and magnetic properties of native defects, alkali and alkaline-earth metal substitutions as disputed in recent theoretical and experimental studies. Our calculations show that the magnetism in undoped In2O3 is originated from In vacancies (VIn) instead of O vacancies. The ferromagnetic (FM) coupling between the moments introduced by VIn is found strong enough to achieve room temperature ferromagnetism. Moreover, FM coupling is also strongly favored in alkali metal doping cases with negative formation energy. For all XIn (XIn=VIn, LiIn, NaIn, and KIn) doped In2O3, the induced magnetic moments are mainly localized on the first shell of O atoms around XIn sites. The FM coupling between the moments induced by XIn defects is activated by intra- and intercorrelation of the XIn–6ONN complexes. A XIn–ONN–InNN–ONN–XIn chain is required to mediate the long-range FM coupling. However, in cases of Mg or Ca doped In2O3, the ground state is nonmagnetic.