title: Temperature-tunable Fano resonance induced by strong coupling between Weyl fermions and phonons in TaAs.
abstract: Strong coupling between discrete phonon and continuous electron-hole pair excitations can induce a pronounced asymmetry in the phonon line shape, known as the Fano resonance. This effect has been observed in various systems. Here we reveal explicit evidence for strong coupling between an infrared-active phonon and electronic transitions near the Weyl points through the observation of a Fano resonance in the Weyl semimetal TaAs. The resulting asymmetry in the phonon line shape, conspicuous at low temperatures, diminishes continuously with increasing temperature. This behaviour originates from the suppression of electronic transitions near the Weyl points due to the decreasing occupation of electronic states below the Fermi level (EF) with increasing temperature, as well as Pauli blocking caused by thermally excited electrons above EF. Our findings not only elucidate the mechanism governing the tunable Fano resonance but also open a route for exploring exotic physical phenomena through phonon properties in Weyl semimetals.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.|Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China.
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Y M
authors.initials: YM
authors.lastname: Dai
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
authors.forename: L X
authors.initials: LX
authors.lastname: Zhao
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
authors.forename: K
authors.initials: K
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
authors.forename: R
authors.initials: R
authors.lastname: Yang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
authors.forename: J Y
authors.initials: JY
authors.lastname: Liu
authors.affiliation: Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China.
authors.forename: H
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100190, China.
authors.forename: G F
authors.initials: GF
authors.lastname: Chen
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.|Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Trugman
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.|Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: J-X
authors.initials: JX
authors.lastname: Zhu
authors.affiliation: Associate Directorate for Chemistry, Life and Earth Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Taylor
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Yarotski
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Prasankumar
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100190, China.
authors.forename: X G
authors.initials: XG
authors.lastname: Qiu