TY  - JOUR
AU  - Orenstein, Gal
AU  - Krapivin, Viktor
AU  - Huang, Yijing
AU  - Zhang, Zhuquan
AU  - de la Peña Muñoz, Gilberto
AU  - Duncan, Ryan A.
AU  - Nguyen, Quynh
AU  - Stanton, Jade
AU  - Teitelbaum, Samuel
AU  - Yavas, Hasan
AU  - Sato, Takahiro
AU  - Hoffmann, Matthias C.
AU  - Kramer, Patrick
AU  - Zhang, Jiahao
AU  - Cavalleri, Andrea
AU  - Comin, Riccardo
AU  - Dean, Mark P. M.
AU  - Disa, Ankit S.
AU  - Först, Michael
AU  - Johnson, Steven L.
AU  - Mitrano, Matteo
AU  - Rappe, Andrew M.
AU  - Reis, David A.
AU  - Zhu, Diling
AU  - Nelson, Keith A.
AU  - Trigo, Mariano
TI  - Observation of polarization density waves in SrTiO<sub>3</sub>
JO  - Nature physics
VL  - 21
IS  - 6
SN  - 1745-2473
CY  - Basingstoke
PB  - Nature Publishing Group
M1  - PUBDB-2025-02006
SP  - 961 - 965
PY  - 2025
N1  - Waiting for fulltext 
AB  - The nature of the incipient ferroelectric transition in SrTiO<sub>3</sub> has been a long-standing puzzle in condensed matter physics. One explanation involves the competition between ferroelectricity and an instability characterized by the mesoscopic modulation of the polarization. These polarization density waves, which should intensify near the quantum critical point, break local inversion symmetry and are difficult to characterize with conventional X-ray scattering methods. Here we probe inversion symmetry breaking at finite momenta and visualize the instability of the polarization at the nanometre scale in SrTiO<sub>3</sub> by combining a femtosecond X-ray free-electron laser with terahertz coherent control methods. We found polar-acoustic collective modes that are soft, particularly at the tens of nanometre scale. These precursor collective excitations provide evidence for the conjectured mesoscopic-modulated phase in SrTiO<sub>3</sub>.  
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1038/s41567-025-02874-0
UR  - https://bib-pubdb1.desy.de/record/631494
ER  -