Thickness dependence of quantum oscillations in Weyl semimetal SrRuO3

Uddipta Kar^1,5*, Chih-Yu Lin^1,7, Yu-Te Hsu^2,6, Bipul Das¹, Cheng-Tung Cheng¹, Akhilesh Kr. Singh¹, Song Yang⁴, Chun-Yen Lin⁴, Chia-Hung Hsu⁴, S. Wiedmann^2,6, Wei-Cheng Lee³, Wei-Li Lee¹

¹Physics, Academia Sinica, Taipei, Nangang, Taiwan
²High Field Magnet Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, Netherlands
³Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902, USA
⁴National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
⁵Nano Science and Technology, Taiwan International Graduate Program, Academia Sinica and National Taiwan university, Taipei, Nangang, Taiwan
⁶Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands
⁷Physics, National Taiwan University, Taipei 10617, Taiwan

* Presenter:Uddipta Kar, email:uddiptakarphysics@gmail.com

Using the adsorption-controlled growth technique with an oxide molecular beam epitaxy (MBE) system, we succeeded to grow high crystalline SrRuO3(SRO) films on SrTiO3(001)(STO) substrates, showing a residual resistivity at T =2.5 K (ρ(2.5 K)) of about  12.31 to 3.24 Ω cm as the SRO film thickness (t) varies from 7.7 to 35.3 nm. Rigorous magnetotransport measurements on SRO films with different ts were performed up to a field strength of about 35 T, where pronounced quantum oscillations with several distinct frequencies were observed. In particular, we uncovered an unusual frequency of about 30 T in the quantum oscillation, which behaves as a small two-dimensional Fermi pocket as confirmed from its angle dependence. The corresponding Landau fan diagram also showed a distinct feature that can be understood within the framework of Weyl-orbit effect, where the top and bottom Fermi-arc surface states collaborate with the bulk Weyl nodes to form a remarkable nonlocal cyclotron orbit. Detailed thickness dependence and angle dependence of the quantum oscillations in SRO films will be presented and discussed.

Keywords: Quantum oscillation, SrRuO3 thin film, Weyl semimetal