Terahertz Coherent Acoustic Phonons in Superlattices of Perovskite Oxides

Chi-Yuan Yang^1,2,4*, Ping-Chun Wu³, Ying-Hao Chu³, Kung-Hsuan Lin⁴

¹Department of Physics, National Taiwan University, Taipei, Taiwan
²Nano-Science and Technology Program, Taiwan International Graduate Program, Taipei, Taiwan
³Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
⁴Institute Of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Chi-Yuan Yang, email:lecteryang@yahoo.com.tw

We utilized time-resolved pump-probe spectroscopy to generate and detect coherent acoustic phonons (CAPs) in SrRuO3/SrTiO3 superlattices. Thanks to the precise manipulation of atomic layers for fabrication of high-quality heterostructures with pulse laser deposition, we demonstrated generation of CAPs up to 1 THz in perovskite oxides for the first time. Dynamics of CAPs from hundreds of GHz to 1 THz were investigated. By introducing a control pulse, coherent control of CAPs was also demonstrated. Numerical simulations were performed to understand the experimental results. We have demonstrated the potential to study acoustic properties of perovskite oxides in THz regime since they can be deposited on the SrRuO3/SrTiO3 superlattices, which serves as the transducer for acoustic generation and detection.

Keywords: strontium titanate, strontium ruthenate, superlattice, pump-probe spectroscopy