Structure and lattice dynamics of binary lead silicate glasses investigated by infrared spectroscopy

Meneses, D. De Sousa; Malki, M.; Echegut, Patrick

doi:10.1016/j.jnoncrysol.2006.02.004

Cited by 157 publications

(42 citation statements)

References 33 publications

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“…39 By simultaneous fitting of both the real and the imaginary part of the dielectric constant, we were able to obtain a series of continuously varying parameters. In the c-axis fitting the Gaussian centered at 33 000 cm −1 (≈4 eV) loses SW below 140 K: we left this oscillator free to vary, as attempts to block it produce a much worse fit.…”

Section: Methodsmentioning

confidence: 99%

Ultrafast optical spectroscopy of the lowest energy excitations in the Mott insulator compound YVO3: Evidence for Hubbard-type excitons

et al. 2012

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Revealing the nature of charge excitations in strongly correlated electron systems is crucial to understanding their exotic properties. Here we use broadband ultrafast pump-probe spectroscopy in the visible range to study low-energy transitions across the Mott-Hubbard gap in the orbitally ordered insulator YVO 3 . Separating thermal and nonthermal contributions to the optical transients, we show that the total spectral weight of the two lowest peaks is conserved, demonstrating that both excitations correspond to the same multiplet. The pump-induced transfer of spectral weight between the two peaks reveals that the low-energy one is a Hubbard exciton, i.e., a resonance or a nearly bound state between a doublon and a holon. Finally, we speculate that the pump-driven spin disorder can be used to quantify the kinetic energy gain of the excitons in a ferromagnetic environment.

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Section: Methodsmentioning

confidence: 99%

Ultrafast optical spectroscopy of the lowest energy excitations in the Mott insulator compound YVO3: Evidence for Hubbard-type excitons

et al. 2012

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“…The absorption was fitted using a Gaussian oscillator model. 19 The optical constants and the film thickness can be deduced from the model. A Bruggeman type effective medium approximation (EMA) layer 20 was also adopted to represent the surface roughness.…”

Section: B Deposition Rate and Optical Propertiesmentioning

confidence: 99%

Characterization of low temperature deposited atomic layer deposition TiO2 for MEMS applications

Huang

Pandraud

Sarro

2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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TiO 2 is an interesting and promising material for micro-/nanoelectromechanical systems (MEMS/ NEMS). For high performance and reliable MEMS/NEMS, optimization of the optical characteristics, mechanical stress, and especially surface smoothness of TiO 2 is required. To overcome the roughness issue of the TiO 2 films due to crystallization during deposition at high temperatures (above 250 C), low temperature (80-120 C) atomic layer deposition (ALD) is investigated. By lowering the deposition temperature, the surface roughness significantly decreases from 3.64 nm for the 300 C deposited crystalline (anatase phase) TiO 2 to 0.24 nm for the 120 C amorphous TiO 2 . However, the layers deposited at low temperature present different physical behaviors comparing to the high temperature ones. The refractive index drops from 2.499 to 2.304 (at 633 nm) and the stress sharply decreases from 684 to 133 MPa. Superhydrophilic surface is obtained for the high temperature deposited TiO 2 under ultraviolet illumination, while little changes are found for the low temperature TiO 2 . The authors demonstrate that by suitable postdeposition annealing, all the properties of the low temperature deposited films recover to that of the 300 C deposited TiO 2 , while the smooth surface profile (less than 1 nm roughness) is maintained. Finally, micromachining of the low temperature ALD TiO 2 by dry etching is also studied.

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“…Structural characterization of these glasses is highly desirable for proper understanding of the changes in the physical properties. Spectroscopic techniques such as nuclear magnetic resonance (NMR) [8][9][10][11][12][13][14], X-ray absorption fine structure (XAFS) [12,15], neutron diffraction and Raman spectroscopy [11,[16][17][18], IR spectroscopy [17,[19][20][21], X-ray photoemission spectroscopy [2,21] and electron spin resonance [22] have been previously used to characterize the structural units in binary silicate glasses.…”

Section: Introductionmentioning

confidence: 99%

Correlation of structural units and chemical stability in SiO2–PbO–Na2O ternary glasses: Spectroscopic methods

Mocioiu

Popa

Neacsu

et al. 2013

Journal of Non-Crystalline Solids

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Structure and lattice dynamics of binary lead silicate glasses investigated by infrared spectroscopy

Cited by 157 publications

References 33 publications

Ultrafast optical spectroscopy of the lowest energy excitations in the Mott insulator compound YVO3: Evidence for Hubbard-type excitons

Ultrafast optical spectroscopy of the lowest energy excitations in the Mott insulator compound YVO3: Evidence for Hubbard-type excitons

Characterization of low temperature deposited atomic layer deposition TiO2 for MEMS applications

Correlation of structural units and chemical stability in SiO2–PbO–Na2O ternary glasses: Spectroscopic methods

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