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Main Authors: Maity, Avishek, Habicht, Klaus, Merz, Michael, Said, Ayman H., Guguschev, Christo, Kojda, Danny, Ryll, Britta, Hoffmann, Jan-Ekkehard, Dittmar, Andrea, Keller, Thomas, Weber, Frank
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.15088
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author Maity, Avishek
Habicht, Klaus
Merz, Michael
Said, Ayman H.
Guguschev, Christo
Kojda, Danny
Ryll, Britta
Hoffmann, Jan-Ekkehard
Dittmar, Andrea
Keller, Thomas
Weber, Frank
author_facet Maity, Avishek
Habicht, Klaus
Merz, Michael
Said, Ayman H.
Guguschev, Christo
Kojda, Danny
Ryll, Britta
Hoffmann, Jan-Ekkehard
Dittmar, Andrea
Keller, Thomas
Weber, Frank
contents The continuous displacive phase transition in SrTiO$_3$ near $T_c \approx 105$ K features a central elastic peak in neutron scattering investigations at temperatures above $T_c$, 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 SrTiO$_3$. 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, be 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 $T_c$, 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 SrTiO$_3$.
format Preprint
id arxiv_https___arxiv_org_abs_2502_15088
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Soft phonon and the central peak at the cubic-to-tetragonal phase transition in SrTiO$_3$
Maity, Avishek
Habicht, Klaus
Merz, Michael
Said, Ayman H.
Guguschev, Christo
Kojda, Danny
Ryll, Britta
Hoffmann, Jan-Ekkehard
Dittmar, Andrea
Keller, Thomas
Weber, Frank
Strongly Correlated Electrons
The continuous displacive phase transition in SrTiO$_3$ near $T_c \approx 105$ K features a central elastic peak in neutron scattering investigations at temperatures above $T_c$, 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 SrTiO$_3$. 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, be 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 $T_c$, 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 SrTiO$_3$.
title Soft phonon and the central peak at the cubic-to-tetragonal phase transition in SrTiO$_3$
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2502.15088