Journal Article

IMPULSE-2025-00079

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Soft phonon and the central peak at the cubic-to-tetragonal phase transition in SrTiO$_{3}$

Maity, A. (Corresponding author)MLZ* ; Habicht, K.MLZ* ; Merz, M. ; Said, A. H. ; Guguschev, C. ; Kojda, D. ; Ryll, B. ; Hoffmann, J.-E. ; Dittmar, A. ; Keller, T.MLZ* ; Weber, F. (Corresponding author)

2025
Inst. Woodbury, NY

Please use a persistent id in citations: doi:10.1103/PhysRevB.111.134108

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.

Keyword(s): Basic research (1st) ; Condensed Matter Physics (2nd)

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Contributing Institute(s):

1. PUMA (PUMA)
2. TRISP (TRISP)

Experiment(s):

1. TRISP: Three axes spin echo spectrometer (SR5b)

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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