Evidence for the weakly coupled electron mechanism in an Anderson-Blount polar metal
Abstract
Over 50 years ago, Anderson and Blount proposed that ferroelectric-like structural phase transitions may occur in metals, despite the expected screening of the Coulomb interactions that often drive polar transitions. Recently, theoretical treatments have suggested that such transitions require the itinerant electrons be decoupled from the soft transverse optical phonons responsible for polar order. However, this decoupled electron mechanism (DEM) has yet to be experimentally observed. Here we utilize ultrafast spectroscopy to uncover evidence of the DEM in LiOsO_3, the first known band metal to undergo a thermally driven polar phase transition (T_c ≈ 140 K). We demonstrate that intra-band photo-carriers relax by selectively coupling to only a subset of the phonon spectrum, leaving as much as 60% of the lattice heat capacity decoupled. This decoupled heat capacity is shown to be consistent with a previously undetected and partially displacive TO polar mode, indicating the DEM in LiOsO_3.
Additional Information
© 2019 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 08 February 2019; Accepted 14 June 2019; Published 19 July 2019. Data availability: The datasets generated are/or analyzed during the current study are available from the corresponding author on reasonable request. This work was supported by the U.S. Department of Energy under Grant no. DE SC0010533. D.H. also acknowledges funding from the David and Lucile Packard Foundation and support for instrumentation from the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (PHY-1733907). N.J.L. acknowledges support from the Institute for Quantum Information and Matter Postdoctoral Fellowship. N.Z.K. was supported by U.S. DOE-BES Grant no. DE-SC0012375. D.P. and J.M.R. were supported by ARO (Award no. W911NF-15-1-0017). Y.G.S. was supported by the National Key Research and Development Program of China (Nos. 2017YFA0302901 and 2016YFA0300604). We thank Rohit Prasankumar for helpful conversations, Qingming Zhang for sharing unpublished Raman data, and Stefano Lupi for sharing unpublished reflectivity results.Attached Files
Published - s41467-019-11172-2.pdf
Supplemental Material - 41467_2019_11172_MOESM1_ESM.pdf
Supplemental Material - 41467_2019_11172_MOESM2_ESM.pdf
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Additional details
- PMCID
- PMC6642157
- Eprint ID
- 97292
- Resolver ID
- CaltechAUTHORS:20190719-102955020
- DE-SC0010533
- Department of Energy (DOE)
- David and Lucile Packard Foundation
- Institute for Quantum Information and Matter (IQIM)
- PHY-1733907
- NSF
- DE-SC0012375
- Department of Energy (DOE)
- W911NF-15-1-0017
- Army Research Office (ARO)
- 2017YFA0302901
- National Key Research and Development Program of China
- 2016YFA0300604
- National Key Research and Development Program of China
- Created
-
2019-07-19Created from EPrint's datestamp field
- Updated
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2022-02-25Created from EPrint's last_modified field
- Caltech groups
- Institute for Quantum Information and Matter