Evidence of a structural quantum critical point in (CaxSr1-x)3Rh4Sn13 from a lattice dynamics study
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Authors
Cheung, YW
Hu, YJ
Imai, M
Tanioku, Y
Kanagawa, H
Murakawa, J
Moriyama, K
Zhang, W
Lai, KT
Yoshimura, K
Kaneko, K
Tsutsui, S
Goh, SK
Publication Date
2018-10-04Journal Title
Physical Review B
ISSN
2469-9950
Publisher
American Physical Society (APS)
Volume
98
Issue
16
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Cheung, Y., Hu, Y., Imai, M., Tanioku, Y., Kanagawa, H., Murakawa, J., Moriyama, K., et al. (2018). Evidence of a structural quantum critical point in (CaxSr1-x)3Rh4Sn13 from a lattice dynamics study. Physical Review B, 98 (16) https://doi.org/10.1103/PhysRevB.98.161103
Abstract
Approaching a quantum critical point (QCP) has been an effective route to
stabilize superconductivity. While the role of magnetic QCPs has been
extensively discussed, similar exploration of a structural QCP is scarce due to
the lack of suitable systems with a continuous structural transition that can
be conveniently tuned to 0~K. Using inelastic X-ray scattering, we examine the
phonon spectrum of the nonmagnetic quasi-skutterudite
(Ca$_{x}$Sr$_{1-x}$)$_3$Rh$_4$Sn$_{13}$, which represents a precious system to
explore the interplay between structural instabilities and superconductivity by
tuning the Ca concentration $x$. We unambiguously detect the softening of
phonon modes around the M point on cooling towards the structural transition.
Intriguingly, at $x=0.85$, the soft mode energy squared at the M point
extrapolates to zero at $(-5.7 \pm 7.7)$~K, providing the first compelling
microscopic evidence of a structural QCP in
(Ca$_{x}$Sr$_{1-x}$)$_3$Rh$_4$Sn$_{13}$. The enhanced phonon density-of-states
at low energy provides the essential ingredient for realizing strong-coupling
superconductivity near the structural QCP.
Relationships
Is supplemented by: https://doi.org/10.17863/CAM.31763
Identifiers
External DOI: https://doi.org/10.1103/PhysRevB.98.161103
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286509
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