Raman scattering in single crystal La 2CuO 4

A.I Maksimow,Z Fisk,O.V Misochko,A.S Cooper,J.P Remeika,I.T Tartakovsky,V.B Timofeev

doi:10.1016/0038-1098(88)90325-0

Abstract

The results of a Raman scattering study of single crystal La 2CuO 4 are reported. Three Ag symmetry modes are observed, rather than the two predicted by group theory. Mode assignments are discussed.

Highlights

The Ramen scattering (RS) experiments were performed using La2C~04~ crystal plates (~3 x 4 x 0.5 mm 3) with well-developed basal plane
The Ramen scattering (RS) spectra were measured for different faces of La2C~04_ ~ crystals in back scattering configuration at T = 300 K using a spectrometer with a microattachment
Since only even vibrations are Raman-active, one may expect that tetragonal crystals of La2Cu04 will display two AI~ symmetry modes corresponding to axial vibrations of La and 0(1) atoms, and two doubly degenerate Eg vibrations of the same atoms

Summary

Introduction

The RS experiments were performed using La2C~04~ crystal plates (~3 x 4 x 0.5 mm 3) with well-developed basal plane. The atoms of oxygen 0(2) lying in the plane of C~ atoms take part in (A2 + B2u + 2Eu) vibrations, whereas Cu atoms with the position summary coinciding with that of an elementary cell give rise to an acoustic branch of (A2u + Eu) vibrations. Since only even vibrations are Raman-active, one may expect that tetragonal crystals of La2Cu04 will display two AI~ symmetry modes corresponding to axial vibrations of La and 0(1) atoms, and two doubly degenerate Eg vibrations of the same atoms.

Results

Conclusion