Discovery of Superconductivity and Electron-Phonon Drag in the Non-Centrosymmetric Weyl Semimetal LaRhGe$_3$

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Hauptverfasser: Oudah, Mohamed, Kung, Hsiang-Hsi, Sahu, Samikshya, Heinsdorf, Niclas, Schulz, Armin, Philippi, Kai, Sanchez, Marta-Villa De Toro, Cai, Yipeng, Kojima, Kenji, Schnyder, Andreas P., Takagi, Hidenori, Keimer, Bernhard, Bonn, Doug A., Hallas, Alannah M.
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Veröffentlicht: 2023
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author Oudah, Mohamed
Kung, Hsiang-Hsi
Sahu, Samikshya
Heinsdorf, Niclas
Schulz, Armin
Philippi, Kai
Sanchez, Marta-Villa De Toro
Cai, Yipeng
Kojima, Kenji
Schnyder, Andreas P.
Takagi, Hidenori
Keimer, Bernhard
Bonn, Doug A.
Hallas, Alannah M.
author_facet Oudah, Mohamed
Kung, Hsiang-Hsi
Sahu, Samikshya
Heinsdorf, Niclas
Schulz, Armin
Philippi, Kai
Sanchez, Marta-Villa De Toro
Cai, Yipeng
Kojima, Kenji
Schnyder, Andreas P.
Takagi, Hidenori
Keimer, Bernhard
Bonn, Doug A.
Hallas, Alannah M.
contents We present an exploration of the effect of electron-phonon coupling and broken inversion symmetry on the electronic and thermal properties of the semimetal LaRhGe$_3$. Our transport measurements reveal evidence for electron-hole compensation at low temperatures, resulting in a large magnetoresistance of 3000% at 1.8 K and 14 T. The carrier concentration is on the order of $10^{21}\rm{/cm}^3$ with high carrier mobilities of $2000~\rm{cm}^2/\rm{Vs}$. When coupled to our theoretical demonstration of symmetry-protected $\textit{almost movable}$ Weyl nodal lines, we conclude that LaRhGe$_3$ supports a Weyl semimetallic state. We discover superconductivity in this compound with a $T_{\text c}$ of 0.39(1) K and $B_{\rm{c}}(0)$ of 2.2(1) mT, with evidence from specific heat and transverse-field muon spin relaxation. We find an exponential dependence in the normal state electrical resistivity below $\sim50$ K, while Seebeck coefficient and thermal conductivity measurements each reveal a prominent peak at low temperatures, indicative of strong electron-phonon interactions. To this end, we examine the temperature-dependent Raman spectra of LaRhGe$_3$ and find that the lifetime of the lowest energy $A_1$ phonon is dominated by phonon-electron scattering instead of anharmonic decay. We conclude that LaRhGe$_3$ has strong electron-phonon coupling in the normal state, while the superconductivity emerges from weak electron-phonon coupling. These results open up the investigation of electron-phonon interactions in the normal state of superconducting non-centrosymmetric Weyl semimetals.
format Preprint
id arxiv_https___arxiv_org_abs_2311_11402
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Discovery of Superconductivity and Electron-Phonon Drag in the Non-Centrosymmetric Weyl Semimetal LaRhGe$_3$
Oudah, Mohamed
Kung, Hsiang-Hsi
Sahu, Samikshya
Heinsdorf, Niclas
Schulz, Armin
Philippi, Kai
Sanchez, Marta-Villa De Toro
Cai, Yipeng
Kojima, Kenji
Schnyder, Andreas P.
Takagi, Hidenori
Keimer, Bernhard
Bonn, Doug A.
Hallas, Alannah M.
Superconductivity
Materials Science
We present an exploration of the effect of electron-phonon coupling and broken inversion symmetry on the electronic and thermal properties of the semimetal LaRhGe$_3$. Our transport measurements reveal evidence for electron-hole compensation at low temperatures, resulting in a large magnetoresistance of 3000% at 1.8 K and 14 T. The carrier concentration is on the order of $10^{21}\rm{/cm}^3$ with high carrier mobilities of $2000~\rm{cm}^2/\rm{Vs}$. When coupled to our theoretical demonstration of symmetry-protected $\textit{almost movable}$ Weyl nodal lines, we conclude that LaRhGe$_3$ supports a Weyl semimetallic state. We discover superconductivity in this compound with a $T_{\text c}$ of 0.39(1) K and $B_{\rm{c}}(0)$ of 2.2(1) mT, with evidence from specific heat and transverse-field muon spin relaxation. We find an exponential dependence in the normal state electrical resistivity below $\sim50$ K, while Seebeck coefficient and thermal conductivity measurements each reveal a prominent peak at low temperatures, indicative of strong electron-phonon interactions. To this end, we examine the temperature-dependent Raman spectra of LaRhGe$_3$ and find that the lifetime of the lowest energy $A_1$ phonon is dominated by phonon-electron scattering instead of anharmonic decay. We conclude that LaRhGe$_3$ has strong electron-phonon coupling in the normal state, while the superconductivity emerges from weak electron-phonon coupling. These results open up the investigation of electron-phonon interactions in the normal state of superconducting non-centrosymmetric Weyl semimetals.
title Discovery of Superconductivity and Electron-Phonon Drag in the Non-Centrosymmetric Weyl Semimetal LaRhGe$_3$
topic Superconductivity
Materials Science
url https://arxiv.org/abs/2311.11402