title: The origin of incipient ferroelectricity in lead telluride.
abstract: The interactions between electrons and lattice vibrations are fundamental to materials behaviour. In the case of group IV-VI, V and related materials, these interactions are strong, and the materials exist near electronic and structural phase transitions. The prototypical example is PbTe whose incipient ferroelectric behaviour has been recently associated with large phonon anharmonicity and thermoelectricity. Here we show that it is primarily electron-phonon coupling involving electron states near the band edges that leads to the ferroelectric instability in PbTe. Using a combination of nonequilibrium lattice dynamics measurements and first principles calculations, we find that photoexcitation reduces the Peierls-like electronic instability and reinforces the paraelectric state. This weakens the long-range forces along the cubic direction tied to resonant bonding and low lattice thermal conductivity. Our results demonstrate how free-electron-laser-based ultrafast X-ray scattering can be utilized to shed light on the microscopic mechanisms that determine materials properties.
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Jiang
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: M
authors.initials: M
authors.lastname: Trigo
authors.affiliation: Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork T12R5CP, Ireland.|Department of Physics, University College Cork, College Road, Cork, Ireland.
authors.forename: I
authors.initials: I
authors.lastname: Savić
authors.affiliation: Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork T12R5CP, Ireland.|Department of Physics, University College Cork, College Road, Cork, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Fahy
authors.affiliation: Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork T12R5CP, Ireland.|Department of Physics, University College Cork, College Road, Cork, Ireland.|Departments of Physics and Materials, Imperial College London, London SW7 2AZ, UK.
authors.forename: É D
authors.initials: ÉD
authors.lastname: Murray
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: C
authors.initials: C
authors.lastname: Bray
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Clark
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: T
authors.initials: T
authors.lastname: Henighan
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kozina
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: M
authors.initials: M
authors.lastname: Chollet
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Glownia
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Hoffmann
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: D
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: O
authors.initials: O
authors.lastname: Delaire
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: May
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: B C
authors.initials: BC
authors.lastname: Sales
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Lindenberg
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: P
authors.initials: P
authors.lastname: Zalden
authors.affiliation: RIKEN SPring-8 Center, Kouto 1-1-1, Sayo, Hyogo 679-5148, Japan.|Department of Chemistry, The School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.affiliation: Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: R
authors.initials: R
authors.lastname: Merlin
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Departments of Physics and Materials, Imperial College London, London SW7 2AZ, UK.
authors.forename: D A
authors.initials: DA
authors.lastname: Reis