Abstract
The continuous displacive phase transition in SrTiO3 near Tc≈105 K features a central elastic peak in neutron-scattering investigations at temperatures above Tc, i.e., before the corresponding soft phonon mode is overdamped upon cooling. The origin of this central peak is still not understood. Here, we report an inelastic x-ray scattering investigation of the cubic-to-tetragonal phase transition in SrTiO3. We compare quantitatively measurements of the soft phonon mode on two differently grown samples and discuss the findings regarding results from thermodynamic and transport probes such as specific heat and thermal conductivity. Furthermore, we use inelastic x-ray scattering to perform elastic scans with both high momentum and milli-electronvolt energy-resolution and, thus, are able to separate elastic intensities of the central peak from low-energy quasielastic phonon scattering. Our results indicate that the evolution of the soft mode is similar in both samples though the intensities of the central peak differ by a factor of four. Measurements revealing anisotropic correlation lengths on cooling towards Tc, indicate that local properties of the crystals to which collective lattice excitations are insensitive are likely at the origin of the central elastic line in SrTiO3.
| Original language | English |
|---|---|
| Article number | 134108 |
| Journal | Physical Review B |
| Volume | 111 |
| Issue number | 13 |
| DOIs | |
| State | Published - Apr 1 2025 |
Funding
This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. The crystal-growth activities at the Leibniz-Institut for Kristallzochtung (IKZ) using the EFG technique were supported by a project of the Leibniz Association under Reference No. SAW-2013-IKZ-2. Larmor diffraction measurements have been performed at the TRISP triple axis spectrometer with neutron resonance spin echo located at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany and operated by Max-Planck-Institut for Festkerperforschung. We thank the MLZ for the allocation of beam time. We thank Ralph Feyerherm for assistance with the thermal-conductivity and heat-capacity measurements which were performed in the CoreLab Quantum Materials, HZB, Berlin, Germany. We thank Martin Rusu for assistance with the measurements which were performed in the X-Ray CoreLab, HZB, Berlin, Germany. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. The crystal-growth activities at the Leibniz-Institut für Kristallzüchtung (IKZ) using the EFG technique were supported by a project of the Leibniz Association under Reference No. SAW-2013-IKZ-2. Larmor diffraction measurements have been performed at the TRISP triple axis spectrometer with neutron resonance spin echo located at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany and operated by Max-Planck-Institut für Festkörperforschung. We thank the MLZ for the allocation of beam time. We thank Ralph Feyerherm for assistance with the thermal-conductivity and heat-capacity measurements which were performed in the CoreLab Quantum Materials, HZB, Berlin, Germany. We thank Martin Rusu for assistance with the measurements which were performed in the X-Ray CoreLab, HZB, Berlin, Germany.