Low Temperature Physics: 42, 580 (2016); https://doi.org/10.1063/1.4960008
Fizika Nizkikh Temperatur: Volume 42, Number 7 (July 2016), p. 738-742    ( to contents , go back )

The specifics of radiative annihilation of self-trapped excitons in KI–Tl crystal at low-temperature deformation

K.Sh. Shunkeyev, N.N. Zhanturina, Z.K. Aimaganbetova, A.A. Barmina, L.N. Myasnikova, Sh.Zh. Sagymbaeva, and D.M. Sergeyev

Актюбинский региональный государственный университет им. К. Жубанова пр. А. Молдагуловой, 34, Актобе, 030000, Казахстан
E-mail: nzhanturina@mail.ru
pos Анотація:

Received April 6, 2016.

Abstract

At the registration of x-ray spectra in KI–Tl crystal the effect of low-temperature uniaxial deformation on the exciton’s mean free path before self-trapping was established. The analysis of the dependence of the in-tensity ratio of thallium center emission (2.85 eV) and luminescence of self-trapped excitons (π-component; 3.3 eV) on the degree of deformation in KI–Tl crystal (3.10–3 mol%) shows that the exciton’s mean free path before self-trapping is commensurate with the intertallium distance (20–27)a at the deformation of ε = 2%, while the corresponding value decreases to (5.35–27)a with the rise of ε ≥ 2–5%. Simulation results based on continuum approximation show that with temperature and the degree of low-temperature deformation increasing the height of excitons self-trapping potential barrier decreases, which is consistent with the reduction of the free exciton path length in KI–Tl crystal.

PACS: 62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances;
PACS: 71.35.–y Excitons and related phenomena;
PACS: 78.55.Fv Solid alkali halides.

Key words: KI–Tl, self-trapped excitons, low-temperature deformation, x-ray spectra, mean free path, potential barrier.

Published online: May 25, 2016

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