scholarly journals Charge transfer gap for T′-RE2CuO4 and T-La2CuO4 as estimated from Madelung potential calculations

2006 ◽  
Vol 445-448 ◽  
pp. 94-96 ◽  
Author(s):  
A. Tsukada ◽  
H. Shibata ◽  
M. Noda ◽  
H. Yamamoto ◽  
M. Naito
Keyword(s):  
Charge Transfer ◽  
Madelung Potential

Surface Band Gaps and Superexchange Interaction in Transition Metal Oxides

1995 ◽  
Vol 401 ◽  
Author(s):  
J. J. M. Pothuizen ◽  
O. Cohen ◽  
G. A. Sawatzky
Keyword(s):  
Charge Transfer ◽  
Transition Metal ◽  
Metal Oxides ◽  
Band Gap ◽  
Transition Metal Oxides ◽  
Band Gaps ◽  
Superexchange Interaction ◽  
Surface Band ◽  
Madelung Potential

AbstractIn this paper, we discuss the change in the band gap of charge transfer insulators for different surface terminations. We have calculated the Madelung potential of the unreconstructed (100) surfaces of the rocksalt structured TM-O compounds (TM = Mn, Fe, Co and Ni). We also considered possible step defects on a (100) surface. The presented results are calculated in both the purely ionic case (TM2+O2−) and in the strong ligand p - cation 4s, phybridization (TM1+O1−) case. In both cases the charge transfer gap, Δ, for the surface is reduced compared to the bulk value. As a consequence of this reduction there is a large increase of the surface superexchange interaction, Jsur, and a decrease of the band gap.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Direct imaging of charge transfer

1996 ◽  
Vol 54 ◽  
pp. 680-681
Author(s):  
Yimei Zhu ◽  
J. Tafto
Keyword(s):  
Charge Transfer ◽  
Electron Diffraction ◽  
Scattering Amplitude ◽  
High Temperature Superconductors ◽  
Charge Carriers ◽  
Image Charge ◽  
Net Charge ◽  
Long Time ◽  
Electron Holes ◽  
First Time

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.

Efficient and stable charge transfer channels for photocatalytic water splitting activity of CdS without sacrificial agents

2020 ◽  
Vol 8 (40) ◽  
pp. 20963-20969 ◽  
Author(s):  
Wei Chen ◽  
Guo-Bo Huang ◽  
Hao Song ◽  
Jian Zhang
Keyword(s):  
Charge Transfer ◽  
Water Splitting ◽  
Photocatalytic Water Splitting ◽  
Transfer Channel ◽  
Efficient Charge ◽  
Transfer Channels

An efficient charge transfer channel for improving the photocatalytic water splitting activity and durability of CdS without sacrificial agents.

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

Magnetic properties of new charge-transfer complexes based on manganese porphyrins

1997 ◽  
Vol 90 (3) ◽  
pp. 407-413
Author(s):  
MARC KELEMEN ◽  
CHRISTOPH WACHTER ◽  
HUBERT WINTER ◽  
ELMAR DORMANN ◽  
RUDOLF GOMPPER ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Transfer ◽  
Charge Transfer Complexes ◽  
Manganese Porphyrins
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