[13a-N106-1~5] 22.1 Joint Session M "Phonon Engineering"

▲ [13a-N106-2] Acoustic vibrational wave transmissions at metal-superlattice interfaces

〇HaiJun Cho¹, Yuzhang Wu², Jiajun Qi³, Yuna Kim¹, Hiromichi Ohta¹, Matsuda Osamu⁴ (1.RIES-Hokkaido Univ., 2.IST-Hokkaido Univ., 3.Life-Hokkaido Univ., 4.Eng-Hokkaido Univ.)

Keywords:Acoustic transmissions, Superlattices

Versatility observed from the vibrational properties of superlattices contributed significantly to our current understanding on the heat conduction in material systems. However, the research interest of scientific community is mostly in the intrinsic heat transport properties of superlattices, and phonon transportation across the interface between superlattices and other materials is poorly understood to date. In this study, we performed pump-probe measurements on a thin Cr transducer on InGaO₃(ZnO)_m (IGZOm) superlattice films to demonstrate how phonon engineering in superlattice can be used to control the transmission of acoustic energy at metal-superlattice interfaces. The transient reflectivity from Cr-IGZOm heterostructures showed noticeable changes in the number of acoustic oscillations within the Cr transducer upon changing the superlattice period (d_SL), indicating changes in the acoustic wave transmission probability from Cr to IGZOm. We address the fundamental physics behind this phenomenon with the existing theoretical models and discuss its implications on the transmission mechanism of acoustic phonons at metal-insulator interfaces.