Surface and Bulk Structural Properties of Single Crystalline Sr3Ru2O7

TL;DR

This study investigates the temperature-dependent surface and bulk structures of Sr3Ru2O7 single crystals, revealing distinct distortions at the surface compared to the bulk and confirming temperature effects on lattice parameters.

Contribution

It provides detailed comparison of surface and bulk structural properties of Sr3Ru2O7 using LEED and XRD, highlighting differences in octahedral distortions and temperature dependence.

Findings

Surface octahedra are more distorted than bulk.

Bulk structure's temperature dependence matches previous neutron studies.

Little structural change occurs with thermal cycling between 300K and 80K.

Abstract

We report temperature and thermal-cycling dependence of surface and bulk structures of double-layered perovskite Sr3Ru2O7 single crystals. The surface and bulk structures were investigated using low-energy electron diffraction (LEED) and single-crystal X-ray diffraction (XRD) techniques, respectively. Single-crystal XRD data is in good agreement with previous reports for the bulk structure with RuO6 octahedral rotation, which increases with decreasing temperature (~ 6.7(6)degrees at 300 K and ~ 8.1(2) degrees at 90 K). LEED results reveal that the octahedra at the surface are much more distorted with a higher rotation angle (~ 12 degrees between 300 and 80 K) and a slight tilt ((4.5\pm2.5) degrees at 300 K and (2.5\pm1.7) degrees at 80 K). While XRD data confirms temperature dependence of the unit cell height/width ratio (i.e. lattice parameter c divided by the average of parameters a and b) found in a prior neutron powder diffraction investigation, both bulk and surface structures display little change with thermal cycles between 300 and 80 K.