photoemission spectrum
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Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 11
Author(s):  
Selma Erat ◽  
Artur Braun ◽  
Samed Çetinkaya ◽  
Saadet Yildirimcan ◽  
Ahmet Emre Kasapoğlu ◽  
...  

Intrinsic and dandelion-like microflower nano-rod structures of boron-doped ZnO thin films were synthesized with an ecofriendly and cost-effective chemical bath deposition technique from an aqueous solution of zinc nitrate hexahdyrate [Zn(NO3)2.6H2O] as a precursor solution and boric acid as a doping solution. The boron concentrations were 0.1, 0.3, 0.5, 1.0, 3.0, 5.0, and 7.0 by volume. Scanning electron micrographs showed that doping with boron appears to hinder the vertical alignment of crystallites. Additionally, independent hexagonal nano-rod structures were observed to coalesce together to form dandelion-like structures on the film’s surface. The atomic ratio of the elements was determined via the X-ray photoemission spectrum technique. There were no substantial changes in the vibration structure of the film upon doping in terms of the Raman spectra. The optical band gap of ZnO (3.28 eV) decreased with B doping. The band gap of the ZnO:B film varied between 3.18 and 3.22 eV. The activation energy of the ZnO was calculated as 0.051 eV, whereas that of the ZnO:B film containing 1.0% B was calculated as 0.013 eV at low temperatures (273–348 K), versus 0.072 eV and 0.183 eV at high temperatures (348–523 K), respectively. Consequently, it can be interpreted that the 1% B-doped ZnO, which has the lowest activation energy at both low and high temperatures, may find some application areas such as in sensors for gases and in solar cells.


Author(s):  
Ru-song Li ◽  
Xiao-hua Zhou ◽  
Zheng Xie ◽  
ling-yun Kong ◽  
Deng-wu Wang ◽  
...  

In order to elucidate the temperature-dependent valence state of Ce ion and the occupation number of Ce 4f electrons in cerium mononitride (CeN), we perform an ab initio calculation on CeN by using a many-body scheme combing density functional theory (DFT) with dynamical mean field theory (DMFT), taking into account the spin-orbit coupling (SOC) interaction and on-site Coulomb repulsion between Ce 4f electrons. Results demonstrate that Ce 4f j=5/2 and j=7/2 manifolds undergo insulating-metallic transition with the increasing of temperature. Ce 4f-conduction electrons hybridization, f-f correlation, SOC interaction and final state effects yield a complicated spectrum function in CeN. Ce 4f atomic configuration transition and hybridization might be responsible for the temperature-dependent occupancy number of Ce 4f electrons and the mixed-valence state in CeN. A fact that localization of Ce 4f electrons, i.e., 4f1 configuration or Ce3+ valence, increases with the increasing of temperature could account for the experimentally observed lattice constant versus temperature data. Finally, the so-called quasiparticle band structure is also discussed for comparison with experimental angle-resolved photoemission spectrum (ARPES).


2021 ◽  
Vol 28 (5) ◽  
Author(s):  
Takayuki Muro ◽  
Tomohiro Matsushita ◽  
Kazumi Sawamura ◽  
Jun Mizuno

A wide-acceptance-angle spherical grid composed of numerous micro cylindrical holes was developed to be used for the retarding grid of a display-type retarding field analyzer (RFA) and to enhance the energy resolution (E/ΔE). Each cylindrical hole with a diameter of 50 µm and a depth of 80 µm is directed to the spherical center. The inner radius of the spherical grid is 40 mm. The holed area corresponds to an acceptance angle of ±52°. The E/ΔE of an RFA equipped with the developed holed grid was estimated to be 2000 from a measured Au 4f photoemission spectrum. A clear photoelectron hologram was observed in the Mo 4p core-level region of MoS2, indicating that the RFA with the holed grid is effective for photoelectron holography.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chong Liu ◽  
Ryan P. Day ◽  
Fengmiao Li ◽  
Ryan L. Roemer ◽  
Sergey Zhdanovich ◽  
...  

AbstractThe mechanism of the enhanced superconductivity in monolayer FeSe/SrTiO3 has been enthusiastically studied and debated over the past decade. One specific observation has been taken to be of central importance: the replica bands in the photoemission spectrum. Although suggestive of electron-phonon interaction in the material, the essence of these spectroscopic features remains highly controversial. In this work, we conduct angle-resolved photoemission spectroscopy measurements on monolayer FeSe/SrTiO3 using linearly polarized photons. This configuration enables unambiguous characterization of the valence electronic structure with a suppression of the spectral background. We consistently observe high-order replica bands derived from various Fe 3d bands, similar to those observed on bare SrTiO3. The intensity of the replica bands is unexpectedly high and different between dxy and dyz bands. Our results provide new insights on the electronic structure of this high-temperature superconductor and the physical origin of the photoemission replica bands.


2021 ◽  
Vol 5 (1) ◽  
pp. 7
Author(s):  
Takuya Kobayashi ◽  
Fumitaka Nishiyama ◽  
Katsumi Takahiro

The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into dark blue-purple by irradiation with 5 keV Ar+ ions to a fluence as low as 1 × 1015 Ar+ cm−2. In the unirradiated copper oxide layer, the copper valence state of Cu2+ and Cu+ and/or Cu0 was included as indicated by the presence of a shake-up satellite line in a photoemission spectrum. While for the irradiated one, the satellite line decreased in intensity, indicating that irradiation resulted in the reduction from Cu2+ to Cu+ and/or Cu0. Furthermore, nuclear reaction analysis using a 16O(d, p)17O reaction with 0.85 MeV deuterons revealed a significant loss of oxygen (5 × 1015 O atoms cm−2) in the irradiated layer. Thus, the chromatic change observed in the present work originated in the irradiation-induced reduction of a copper oxide.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
S. Di Sabatino ◽  
J. Koskelo ◽  
J. A. Berger ◽  
P. Romaniello

Author(s):  
Takuya Kobayashi ◽  
Fumitaka Nishiyama ◽  
Katsumi Takahiro

The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into blue-purple by irradiation with 5 keV Ar+ ions to a fluence as low as 1 1015 Ar+ cm–2. In the unirradiated copper oxide layer, the copper valence state of Cu2+ as well as Cu+ and/or Cu0 was included as indicated by the presence of a shake-up satellite line in a photoemission spectrum. While for the irradiated one, the satellite line decreased in intensity, indicating that irradiation resulted in the reduction from Cu2+ to Cu+ and/or Cu0. Furthermore, nuclear reaction analysis using a 16O(d, p)17O reaction with 0.85 MeV deuterons revealed a significant loss of oxygen (51015 O atoms cm–2) in the irradiated layer. Thus, the chromatic change observed in the present work originated in the irradiation-induced reduction of a copper oxide.


2020 ◽  
Vol 101 (3) ◽  
Author(s):  
Adam Kłosiński ◽  
Dmitri V. Efremov ◽  
Jeroen van den Brink ◽  
Krzysztof Wohlfeld

AIP Advances ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 115106
Author(s):  
Zengli Huang ◽  
Ying Wu ◽  
Yanfei Zhao ◽  
Lin Shi ◽  
Rong Huang ◽  
...  

2019 ◽  
Vol 26 (2) ◽  
pp. 180-181
Author(s):  
A. Herrera-Gomez ◽  
J.F. Fabian-Jocobi ◽  
O. Cortazar-Martinez ◽  
Abraham Cardona-Cardona ◽  
Joaquin-Gerardo Raboño-Borbolla

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