Localized excitations in diluted magnetic Cd1−xMnxTe semiconductor ternary alloys and CdTe/Cd1−xMnxTe superlattices

Talwar, Devki N.; Holliday, Kito

doi:10.1016/s0921-4526(98)01425-2

Cited by 10 publications

(5 citation statements)

References 16 publications

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“…The calculated dispersion (solid curve) is taken from the rigid ion model calculation in Ref. [16], while the open circles (᭺) are experimental inelastic neutron scattering results taken from Ref. [17].…”

Section: Resultsmentioning

confidence: 99%

Polarized far infrared magnetoplasmon reflectivity of doped Cd_xMn_1–xTe semimagnetic semiconductor in the Voigt configuration

Shayesteh

Hidari

2007

Physica Status Solidi (b)

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Calculations of the p-polarized far infrared magnetoplasmon reflectivity of semimagnetic semiconductor Cd x Mn 1-x Te doped ternary alloy in the presence of a magnetic field parallel to the surface of the sample (the Voigt geometry) are used to investigate magnetoplasmon and zone center optical phonon frequencies. It is assumed that the sample is characterized by a dielectric tensor in which the optical phonon contribution and free carriers (plasmon and cyclotron response) are included. The results show that the transverse optical phonon mode is sensitive to the alloy composition, x, and can be used to determine the value of x. The longitudinal optical phonon frequencies are shifted due to phonon-plasmon coupling in doped samples. Also, the influence of composition on the vibrational modes in zinc blende Cd x Mn 1-x Te is described within a modified random element isodisplacement (MREI) approach. By indicating the plasmon and cyclotron frequencies from p-polarized reflectivity spectra and the Voigt permittivity, we calculated the carrier concentration and the effective masses of the carriers. Furthermore, we indicate the frequencies of the phonons at the Г, K, X and L high symmetry points of the Brillouin zone based on a microscopic secondneighbor rigid ion model (RIM).

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Section: Resultsmentioning

confidence: 99%

Polarized far infrared magnetoplasmon reflectivity of doped Cd_xMn_1–xTe semimagnetic semiconductor in the Voigt configuration

Shayesteh

Hidari

2007

Physica Status Solidi (b)

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“…A good deal of information from EXAFS is synthesized in the parallel and perpendicular Einstein frequencies ν and ν ⊥ . The Einstein frequencies listed in table 2 can be compared with the phonon dispersion curves and the corresponding vibrational densities of states (VDOS) of Ge [48], CdTe [49] and CuCl [24]. The TA modes of tetrahedral semiconductors are characterized by low-energy dispersion curves, which become flat away from the Brillouin zone centre.…”

Section: Discussionmentioning

confidence: 99%

Negative thermal expansion in crystals with the zincblende structure: an EXAFS study of CdTe

All

Dalba

Diop

et al. 2012

J. Phys.: Condens. Matter

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The extended x-ray absorption fine structure (EXAFS) has been measured at both the K edges of cadmium and tellurium in CdTe, from liquid helium to room temperature, in order to investigate the local thermodynamic behaviour. The temperature dependences of the structural parameters obtained from the separate analysis of the two edges are perfectly consistent. The positive contribution to the thermal expansion due to the bond stretching and the negative contribution due to the tension effects are disentangled and quantified in terms of the bond thermal expansion and the perpendicular mean square relative displacement. The comparison with previous EXAFS results for Ge and CuCl shows that relevant correlations can be established between a number of local parameters measured by means of EXAFS and the properties of the lattice negative thermal expansion of tetrahedrally bonded semiconductors. The effective force constants derived from the EXAFS are compared with the force constants of a valence force field model.

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“…Actually, such a fit is highly unstable, in view of the strong similarity between the two models, which leads to a strong correlation between Einstein frequency and Debye temperature. In any case, it is interesting that the DW of CdTe is well reproduced by summing a Debye model with the diffraction Debye temperature 143 K (Zubík & Valvoda, 1975;Stewart, 1983) and an Einstein model with a frequency centred on the peak of optic modes in the vibrational density of states (Talwar & Holliday, 1999). …”

Section: Einstein and Debye Modelsmentioning

confidence: 99%

On EXAFS Debye-Waller factor and recent advances

2015

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The effects of structural and vibrational disorder on the EXAFS signals are parameterized in terms of the Debye Waller (DW) factor. Here the vibrational contribution is addressed, which for most systems can be singled out by studying the temperature dependence of the EXAFS DW factor, which corresponds to a good accuracy to the parallel mean square relative displacement (MSRD) around the inter-atomic equilibrium distance. By comparing the first-shell EXAFS thermal expansion with the crystallographic thermal expansion one can evaluate the perpendicular MSRD. The results of recent measurements on copper and on several tetrahedral semiconductors are here critically compared and some properties of the MSRDs are discussed, such as the dependence of correlation, force constants and vibrational anisotropy on crystal structure and bond ionicity as well as the relative merits of the correlated Debye and Einstein models. The anharmonic contribution to the parallel MSRD of CdTe has been evaluated and a quasi-harmonic analysis has been attempted, leading to an estimation of the bond Grü neisen parameter.

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Localized excitations in diluted magnetic Cd1−xMnxTe semiconductor ternary alloys and CdTe/Cd1−xMnxTe superlattices

Cited by 10 publications

References 16 publications

Polarized far infrared magnetoplasmon reflectivity of doped Cd_xMn_1–xTe semimagnetic semiconductor in the Voigt configuration

Polarized far infrared magnetoplasmon reflectivity of doped Cd_xMn_1–xTe semimagnetic semiconductor in the Voigt configuration

Negative thermal expansion in crystals with the zincblende structure: an EXAFS study of CdTe

On EXAFS Debye-Waller factor and recent advances

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Localized excitations in diluted magnetic Cd1−xMnxTe semiconductor ternary alloys and CdTe/Cd1−xMnxTe superlattices

Cited by 10 publications

References 16 publications

Polarized far infrared magnetoplasmon reflectivity of doped CdxMn1–xTe semimagnetic semiconductor in the Voigt configuration

Polarized far infrared magnetoplasmon reflectivity of doped CdxMn1–xTe semimagnetic semiconductor in the Voigt configuration

Negative thermal expansion in crystals with the zincblende structure: an EXAFS study of CdTe

On EXAFS Debye-Waller factor and recent advances

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Product

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Polarized far infrared magnetoplasmon reflectivity of doped Cd_xMn_1–xTe semimagnetic semiconductor in the Voigt configuration

Polarized far infrared magnetoplasmon reflectivity of doped Cd_xMn_1–xTe semimagnetic semiconductor in the Voigt configuration