Lee Jung-Woo, Kim Jiyeong, Eom Kitae, Jeon Jaeyoung, Kim Young Chul, Kim Hwan Sik, Ahn Yeong Hwan, Kim Sungkyu, Eom Chang-Beom, Lee Hyungwoo
KIURI Institute, Yonsei University, Seoul 03722, Republic of Korea.
Department of Physics, Ajou University, Suwon 16499, Republic of Korea.
J Phys Chem Lett. 2022 Jun 23;13(24):5618-5625. doi: 10.1021/acs.jpclett.2c01163. Epub 2022 Jun 15.
SrRuO (SRO) has emerged as a promising quantum material due to its exotic electron correlations and topological properties. In epitaxial SRO films, electron scattering against lattice phonons or defects has been considered as only a predominant mechanism accounting for electronic properties. Although the charge trapping by polar defects can also strongly influence the electronic behavior, it has often been neglected. Herein, we report strong interfacial charge trapping in ultrathin SRO films on SrTiO (STO) substrates probed by noise spectroscopy. We find that oxygen vacancies in the STO cause stochastic interfacial charge trapping, resulting in high electrical noise. Spectral analyses of the photoinduced noise prove that the oxygen vacancies buried deep in the STO can effectively contribute to the charge trapping process. These results unambiguously reveal that electron transport in ultrathin SRO films is dominated by the carrier number fluctuation that correlates with interfacial charge trapping.
由于其奇异的电子关联和拓扑性质，SrRuO（SRO）已成为一种有前途的量子材料。在外延SRO薄膜中，电子与晶格声子或缺陷的散射一直被认为是决定电子性质的主要机制。尽管极性缺陷的电荷俘获也会强烈影响电子行为，但它常常被忽视。在此，我们通过噪声光谱法报道了在SrTiO（STO）衬底上的超薄SRO薄膜中存在强烈的界面电荷俘获现象。我们发现STO中的氧空位会导致随机的界面电荷俘获，从而产生高电噪声。光致噪声的光谱分析证明，深埋在STO中的氧空位能够有效地促进电荷俘获过程。这些结果明确表明，超薄SRO薄膜中的电子输运由与界面电荷俘获相关的载流子数涨落主导。
