Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 62: Focus Session: SrTiO3: A Versatile Material from Bulk Quantum Paraelectric to 2D Superconductor I (joint session TT/KFM/MA/O)
TT 62.7: Vortrag
Donnerstag, 21. März 2024, 12:30–12:45, H 0104
Dynamics of the critical phonon modes in quantum paraelectric SrTiO3 — •Shiyu Deng1,2, Charles S. Haines1,3, Matthew J. Coak1,4, Alexandre Ivanov2, Andrea Piovano2, Andrew R. Wildes2, and Siddharth S. Saxena1 — 1Cavendish Laboratory, University of Cambridge — 2Institut Laue-Langevin — 3University of East Anglia — 4University of Birmingham
The proximity of SrTiO3 to a ferroelectric quantum critical point (FE QCP) has become a promising new branch of the study of quantum critical phenomena. New forms of quantum order have been reported in SrTiO3 different from the quantum paraelectric state via dielectric measurements.
We report our recently performed triple-axis inelastic neutron scattering experiments on single-crystal SrTiO3 at the temperature and pressure region of interest. These were the first direct measurements deep into the enigmatic ’quantum polar-acoustic state’ in the vicinity of the FE QCP. Measurements are taken at and around q = 0 in multiple directions in reciprocal space to explore the transverse acoustic and soft optical phonon modes and their hybridization. In addition, we explore how pressure affects the underlying phonon modes in SrTiO3. Our observations address directly the coupling of the soft optical mode with the acoustic phonons, and its response to external pressure. We believe this could help us understand the importance of anharmonic lattice dynamics and quantum fluctuations in SrTiO3.
Keywords: inelastic neutron scattering; ferroelectric quantum criticality