Optical transitions between surface states on cleaved CdTe(110)

1993 ◽  
Vol 47 (24) ◽  
pp. 16663-16666 ◽  
Author(s):  
B. Kowalski ◽  
A. Cricenti ◽  
S. Selci ◽  
R. Generosi ◽  
B. A. Orlowski ◽  
...  
Keyword(s):  
Surface States ◽  
Optical Transitions

scholarly journals Спектры пропускания квантовых ям и пленок на основе HgTe в дальнем ИК-диапазоне

2018 ◽  
Vol 60 (4) ◽  
pp. 774
Author(s):  
М.Л. Савченко ◽  
Н.Н. Васильев ◽  
А.С. Ярошевич ◽  
Д.А. Козлов ◽  
З.Д. Квон ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Surface States ◽  
Far Infrared ◽  
Infrared Range ◽  
Optical Transitions ◽  
Interband Transitions ◽  
New Class ◽  
Transmission And Reflection Spectra ◽  
Bulk Band ◽  
Transmission And Reflection

AbstractStrained 80-nm-thick HgTe films belong to a new class of materials referred to as three-dimensional topological insulators (i.e., they have a bulk band gap and spin-nondegenerate surface states). Though there are a number of studies devoted to analysis of the properties of surface states using both transport and magnetooptical techniques in the THz range, the information about direct optical transitions between bulk and surface bands in these systems has not been reported. This study is devoted to the analysis of transmission and reflection spectra of HgTe films of different thicknesses in the far-infrared range recorded in a wide temperature range in order to detect the above interband transitions. A peculiarity at 15 meV, which is sensitive to a change in the temperature, is observed in spectra of both types. Detailed analysis of the data obtained revealed that this feature is related to absorption by HgTe optical phonons, while the interband optical transitions are suppressed.

scholarly journals Оптические и транспортные свойства эпитаксиальных пленок Pb-=SUB=-0.74-=/SUB=-Sn-=SUB=-0.26-=/SUB=-Te(In) с модифицируемой поверхностью

2020 ◽  
Vol 54 (9) ◽  
pp. 896
Author(s):  
А.В. Иконников ◽  
В.C. Дудин ◽  
А.И. Артамкин ◽  
А.Н. Акимов ◽  
А.Э. Климов ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Comparative Analysis ◽  
Transport Properties ◽  
Relaxation Times ◽  
Surface States ◽  
Charge Carriers ◽  
Relaxation Processes ◽  
Optical Transitions ◽  
Nonequilibrium Charge Carriers ◽  
Characteristic Features

Abstract The results of studies of the optical and transport properties of epitaxial Pb_0.74Sn_0.26Te(In) films with a differently treated surface are presented. A comparative analysis of the results makes it possible to establish that the characteristic features of the photoconductivity spectra are defined by processes in the bulk while the surface states have practically no effect on the spectra. At the same time, the photoresponse kinetics and the rate of relaxation processes are heavily dependent on the state of the surface. The characteristic relaxation times of nonequilibrium charge carriers (about several milliseconds) are such that it is possible to use the methods of standard Fourier-transform spectroscopy to characterize optical transitions in the bulk.

Zero-loss omega-filtered REM and RHEED on the new Zeiss 912

1991 ◽  
Vol 49 ◽  
pp. 616-617
Author(s):  
J.C.H. Spence ◽  
J. Mayer
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Surface States ◽  
Ccd Camera ◽  
Dark Field ◽  
Ion Pump ◽  
Magnetic Imaging ◽  
Reflection Electron Microscopy ◽  
Diffraction Patterns ◽  
Large Background

The Zeiss 912 is a new fully digital, side-entry, 120 Kv TEM/STEM instrument for materials science, fitted with an omega magnetic imaging energy filter. Pumping is by turbopump and ion pump. The magnetic imaging filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient parallel (area) detection. The energy loss intensity distribution may also be displayed on the screen, and recorded by scanning it over the PMT supplied. If a CCD camera is fitted and suitable new software developed, “parallel ELS” recording results. For large fields of view, filtered images can be recorded much more efficiently than by Scanning Reflection Electron Microscopy, and the large background of inelastic scattering removed. We have therefore evaluated the 912 for REM and RHEED applications. Causes of streaking and resonance in RHEED patterns are being studied, and a more quantitative analysis of CBRED patterns may be possible. Dark field band-gap REM imaging of surface states may also be possible.

OPTICAL TRANSITIONS BETWEEN SPIN-POLARIZED BANDS IN MAGNETIC CHROMIUM SPINELS

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-932-C1-933 ◽  
Author(s):  
H. W. LEHMANN ◽  
G. HARBEKE ◽  
H. PINCH
Keyword(s):  
Optical Transitions ◽  
Spin Polarized

VOLUME DEPENDENCE OF OPTICAL TRANSITIONS IN GaAs : PHOTOMODULATED REFLECTIVITY

1984 ◽  
Vol 45 (C8) ◽  
pp. C8-57-C8-60 ◽  
Author(s):  
M. Hanfland ◽  
K. Syassen ◽  
N. E. Christensen
Keyword(s):  
Optical Transitions ◽  
Volume Dependence
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