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Zero‐Phonon Lines: The Effect of a Strong Softening of Elastic Springs in the Excited State
Author(s) -
Hizhnyakov V.,
Kaasik H.,
Sildos I.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200211)234:2<644::aid-pssb644>3.0.co;2-e
Subject(s) - phonon , dephasing , excited state , condensed matter physics , physics , instability , zero (linguistics) , softening , line (geometry) , atomic physics , quantum mechanics , mathematics , linguistics , philosophy , geometry
The optical dephasing, caused by a quadratic interaction with acoustic phonons, is studied on the basis of the nonperturbative theory. The effect of a strong weakening of the elastic springs on the electronic transition is studied. It is found that, if the weakening brings the system close to the dynamical instability, then the usual ∝ T 7 dependence of the homogeneous width of a zero‐phonon line (ZPL) is replaced by the ∝ T 3 dependence in a broad temperature interval. An equation is derived which describes the additional broadening of a ZPL caused by the dynamical instability of the final state. The model explains the temperature broadening and shift of the zero‐phonon lines of some nitrogen‐containing centers in diamond crystals.