Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: UMLS:C0004135 (
ATM
)
13,001
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
A comprehensive lattice dynamical study is reported to emphasize the vibrational behavior of perfect/imperfect zinc-blende (zb) ZnSe,
MnSe
and Zn
1-x
Mn
x
Se alloys. Low temperature far-infrared (FIR) reflectivity measurements performed on a series of molecular beam epitaxy grown Zn
1-x
Mn
x
Se/GaAs (001) epilayers have a typical 'intermediate-phonon-mode' behavior. Besides perceiving ZnSe- and
MnSe
-like TO-phonon resonances, the study also revealed a weak Mn alloy-disorder mode below
MnSe
band. A classical effective-medium theory of multilayer optics is used to evaluate dielectric tensors of both epilayers and substrate for simulating reflectivity and transmission spectra of ultrathin epifilms and superlattices at near normal and/or oblique incidence. In the framework of a realistic rigid-ion model and exploiting an average
t
-matrix Greens function (ATM-GF) theory we appraised the vibrational properties of nitrogen and phosphorous doped Zn-Mn chalcogenides. Lattice relaxations around isolated N
Se
(P
Se
) defects in ZnSe and zb
MnSe
are evaluated by first principles bond-orbital model that helped construct perturbation models for simulating the localized vibrational modes (LVMs). Calculated shift of impurity modes for isotopic
14
N
Se
(
15
N
Se
) defects in ZnSe offered a strong revelation of an inflexible defect-host interaction. By retaining force constant change parameter of
14
N
Se
(
15
N
Se
) in heavily N-doped ZnSe, the
ATM
-GF theory predicted (a) three non-degenerate LVMs for the photoluminescence defect center
V
Se
-Zn-
14
N
Se
(
V
Se
-Zn-
15
N
Se
) of
C
s
symmetry, and (b) six impurity modes for the second nearest-neighbor N
Se
-Zn-N
Se
pair defect of
C
2v
symmetry. From the range of simulated defect modes, we have ruled out the possibility of N-pairs and justified the presence of V
Se
-Zn-N
Se
complex centers - likely to be responsible for the observed large absorption bandwidth in highly N-doped ZnSe. High resolution measurements of FIR absorption and/or Raman scattering spectroscopy are needed to validate the accuracy of our theoretical conjectures.
...
PMID:Simulating far infrared spectra of Zn
1-x
Mn
x
Se/GaAs epifilms, MnSe/ZnSe superlattices and predicting impurity modes of N, P defects in Zn
1-x
Mn
x
Se. 2822 67
