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Main Authors: Chu, Zhaodong, Yang, Junyi, Li, Yan, Hwangbo, Kyle, Wen, Jianguo, Bielinski, Ashley R., Zhang, Qi, Martinson, Alex B. F., Hruszkewycz, Stephan, Fong, Dillon D., Xu, Xiaodong, Norman, Michael R., Bhattacharya, Anand, Wen, Haidan
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2409.02073
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author Chu, Zhaodong
Yang, Junyi
Li, Yan
Hwangbo, Kyle
Wen, Jianguo
Bielinski, Ashley R.
Zhang, Qi
Martinson, Alex B. F.
Hruszkewycz, Stephan
Fong, Dillon D.
Xu, Xiaodong
Norman, Michael R.
Bhattacharya, Anand
Wen, Haidan
author_facet Chu, Zhaodong
Yang, Junyi
Li, Yan
Hwangbo, Kyle
Wen, Jianguo
Bielinski, Ashley R.
Zhang, Qi
Martinson, Alex B. F.
Hruszkewycz, Stephan
Fong, Dillon D.
Xu, Xiaodong
Norman, Michael R.
Bhattacharya, Anand
Wen, Haidan
contents Understanding surface collective dynamics in quantum materials is crucial for advancing quantum technologies. For example, surface phonon modes in quantum paraelectrics are thought to play an essential role in facilitating interfacial superconductivity. However, detecting these modes, especially below 1 terahertz (THz), is challenging due to limited sampling volumes and the need for high spectroscopic resolution. Here, we report surface soft transverse optical (TO1) phonon dynamics in KTaO3 and SrTiO3 by developing surface-sensitive spintronic THz spectroscopy that can sense the collective modes only a few nanometers deep from the surface. In KTaO3, the TO1 mode softens and sharpens with decreasing temperature, leveling off at 0.7 THz. In contrast, this mode in SrTiO3 broadens significantly below the quantum paraelectric crossover and coincides with the hardening of a sub-meV phonon mode related to the antiferrodistortive transition. These observations that deviate from their bulk properties may have implications for interfacial superconductivity and ferroelectricity. The developed technique opens opportunities for sensing low-energy surface excitations.
format Preprint
id arxiv_https___arxiv_org_abs_2409_02073
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Revealing subterahertz atomic vibrations in quantum paraelectrics by surface-sensitive spintronic terahertz spectroscopy
Chu, Zhaodong
Yang, Junyi
Li, Yan
Hwangbo, Kyle
Wen, Jianguo
Bielinski, Ashley R.
Zhang, Qi
Martinson, Alex B. F.
Hruszkewycz, Stephan
Fong, Dillon D.
Xu, Xiaodong
Norman, Michael R.
Bhattacharya, Anand
Wen, Haidan
Materials Science
Mesoscale and Nanoscale Physics
Understanding surface collective dynamics in quantum materials is crucial for advancing quantum technologies. For example, surface phonon modes in quantum paraelectrics are thought to play an essential role in facilitating interfacial superconductivity. However, detecting these modes, especially below 1 terahertz (THz), is challenging due to limited sampling volumes and the need for high spectroscopic resolution. Here, we report surface soft transverse optical (TO1) phonon dynamics in KTaO3 and SrTiO3 by developing surface-sensitive spintronic THz spectroscopy that can sense the collective modes only a few nanometers deep from the surface. In KTaO3, the TO1 mode softens and sharpens with decreasing temperature, leveling off at 0.7 THz. In contrast, this mode in SrTiO3 broadens significantly below the quantum paraelectric crossover and coincides with the hardening of a sub-meV phonon mode related to the antiferrodistortive transition. These observations that deviate from their bulk properties may have implications for interfacial superconductivity and ferroelectricity. The developed technique opens opportunities for sensing low-energy surface excitations.
title Revealing subterahertz atomic vibrations in quantum paraelectrics by surface-sensitive spintronic terahertz spectroscopy
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2409.02073