Absorption cross sections and number densities of electron and hole polarons in congruently melting LiNbO(3)

J Phys Condens Matter. 2009 Jan 7;21(1):015906. doi: 10.1088/0953-8984/21/1/015906. Epub 2008 Dec 8.

Abstract

The number densities and absorption cross sections of both optically generated and reduction-induced small electron and hole polarons in LiNbO(3) are determined by means of time-resolved pump-multiprobe spectroscopy. The data are obtained for free (Nb(Nb)(4+)) and bound (Nb(Li)(4+)) electron polarons, bound Nb(Li)(4+):Nb(Nb)(4+) electron bipolarons, and bound O(-) hole polarons. The peak absorption cross sections are in the range of σ(pol)≈(4-14) × 10(-22) m(2), comparable to that for Fe(2+). In all cases the ratio of occupied to unoccupied polaronic sites is less than 10(-2).