Research: CDW

		It is generally accepted that magnetic interactions are important in cuprate and Fe-based superconductors. The parent phase in both materials is antiferromagnetic; magnetic resonances are observed via neutron scattering in the superconducting state in both families; and the pairing symmetries in both families (including the multiplicity of pairing symmetries in Fe-based superconductors) can be naturally understood in terms of the dominant spin fluctuations. However, it is becoming increasingly apparent that charge ordered states are also present in the phase diagrams of both families, raising broader questions about the inter-relation of these other types of ordered states and their fluctuations with superconductivity. A large part of our research in the field of Fe-based superconductors is directed towards understanding the effects of nematic order and nematic fluctuations on the emergent superconductivity. A second area of study, more relevant to (motivated by) the cuprates than the Fe-based superconductors, relates to understanding the role(s) played by charge density wave (CDW) correlations and fluctuations in tetragonal materials, including effects due to the presence of disorder. Here we seek model systems to explore these effects in isolation from any incipient magnetic order. More broadly, there are many open questions simply regarding CDW formation in quasi-2D materials, including the relative importance of electron-phonon coupling and Fermi surface nesting, motivating a careful investigation of such systems. Over the last few years we have shown that the rare earth (R) tri-tellurides RTe₃ are just such model materials, hosting a unidirectional or, in some cases, bidirectional, incommensurate CDW. As such, they provide us with a unique opportunity to study the electronic structure of a pseudo-tetragonal material deep in such a state, to understand the driving force behind the instability, and indeed to explore how that state is perturbed by disorder. The image shows recent results demonstrating the effect of Pd intercalation (x) on the phase diagram of ErTe₃, which hosts two mutually transverse incommensurate CDWs. Background shading indicates the magnitude of CDW correlations along the two in-plane axes: blue signifies the primary CDW and red signifies the secondary. As disorder increases, the material begins to exhibit short range correlations along both directions (indicated by purple shading). True long-range-ordered CDW phases exist only on the x = 0 axis. Strong enough disorder results in a superconducting (yellow) ground state.
Publications
Key references:
Suppression of charge density wave order by disorder in Pd-intercalated ErTe₃ Wave-vector-dependent electron-phonon coupling and the charge-density-wave transition in TbTe₃ Effect of chemical pressure on the charge density wave transition in rare earth tritellurides RTe₃ Fermi surface reconstruction in the CDW state of CeTe₃ observed by photoemission
Recent publications:
Evidence for Realignment of the Charge Density Wave State in ErTe₃ and TmTe₃ under Uniaxial Stress via Elastocaloric and Elastoresistivity Measurements Coherent modulation of quasiparticle scattering rates in a photoexcited charge-density-wave system Anomalous thermal transport and strong violation of Wiedemann-Franz law in the critical regime of a charge density wave transition Role of Equilibrium Fluctuations in Light-Induced Order Nonequilibrium charge-density-wave order beyond the thermal limit Ultrafast formation of domain walls of a charge density wave in SmTe₃ Robust superconductivity intertwined with charge density wave and disorder in Pd-intercalated ErTe₃ Magnetic breakdown and charge density wave formation: A quantum oscillation study of the rare-earth tritellurides Interplay of charge density wave states and strain at the surface of CeTe₂ Light-induced charge density wave in LaTe₃ Disorder-induced suppression of charge density wave order: STM study of Pd-intercalated ErTe₃ Dynamical Slowing-Down in an Ultrafast Photoinduced Phase Transition Suppression of charge density wave order by disorder in Pd-intercalated ErTe₃
Additional publications:
Click for additional publications Coherent order parameter dynamics in SmTe₃ Evidence for topological defects in a photoinduced phase transition Competing soft phonon modes at the charge-density-wave transitions in DyTe₃ Determination of the resistivity anisotropy of orthorhombic materials via transverse resistivity measurements Multiple charge density wave states at the surface of TbTe₃ Charge density wave modulation and gap measurements in CeTe₃ Persistent order due to transiently enhanced nesting in an electronically excited charge density wave Ultrafast resonant soft x-ray diffraction dynamics of the charge density wave in TbTe₃ Wave-vector-dependent electron-phonon coupling and the charge-density-wave transition in TbTe₃ Classification of Collective Modes in a Charge Density Wave by Momentum-Dependent Modulation of the Electronic Band Structure Pressure dependence of the charge-density-wave and superconducting states in GdTe₃, TbTe₃, and DyTe₃ Charge transfer and multiple density waves in the rare earth tellurides Incoherent Topological Defect Recombination Dynamics in TbTe₃ Alternative route to charge density wave formation in multiband systems Resonant enhancement of charge density wave diffraction in the rare-earth tritellurides Incommensurate magnetic order in TbTe₃ Ultrafast electron dynamics in the charge density wave material TbTe₃ Anharmonic order-parameter oscillations and lattice coupling in strongly driven 1T-TaS₂ and TbTe₃ charge-density-wave compounds: A multiple-pulse femtosecond laser spectroscopy study Coherent dynamics of macroscopic electronic order through a symmetry breaking transition Temperature dependence of the excitation spectrum in the charge-density-wave ErTe₃ and HoTe₃ systems Raman scattering evidence for a cascade evolution of the charge-density-wave collective amplitude mode Fermi surface evolution across multiple CDW transitions in ErTe₃ Observation of two separate charge density wave transitions in Gd₂Te₅ via transmission electron microscopy and high-resolution X-ray diffraction Optical properties of the charge density wave rare earth tritelluride compounds: a view on PrTe3 Pressure induced superconducting phase in the charge density wave compound TbTe3 Pressure-induced quenching of the charge-density-wave state in rare-earth tritellurides observed by x-ray diffraction High pressure transport and thermodynamic properties of CeTe3 Pressure dependence of the single particle excitation in the charge-density-wave CeTe3 system Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe3 (R = Ho, Dy, Tb) Evidence for coupling between charge density waves and phonons in two-dimensional rare earth tellurides Transient Electronic Structure and Melting of a Charge Density Wave in TbTe3 De Haas-van Alphen oscillations in the charge-density wave compound lanthanum tritelluride (LaTe3) Magnetic properties of the charge density wave compounds RTe3, R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er & Tm Optical properties of the charge-density-wave polychalcogenide compounds R2Te5 (R=Nd, Sm and Gd) Angle-resolved photoemission study of the evolution of band structure and charge density wave properties in RTe3 Pressure dependence of the optical properties of the charge-density-wave compound LaTe2 Charge density wave formation in R2Te5 (R =Nd, Sm, Gd) Effect of chemical pressure on the charge density wave transition in rare earth tritellurides RTe3 STM Studies of TbTe3: Evidence for a Fully Incommensurate Charge Density Wave Optical properties of the Ce and La ditelluride charge density wave compounds Pressure dependence of the charge-density-wave gap in rare-earth tri-tellurides Chemical pressure and hidden one-dimensional behavior in rare earth tri-telluride charge density wave compounds Thermodynamic and transport properties of YTe3, LaTe3 and CeTe3 Electronic structure and charge density wave formation in LaTe1.95 and CeTe2.00 Fermi surface nesting and charge density wave formation in rare earth tritellurides Fermi surface reconstruction in the CDW state of CeTe3 observed by photoemission
Theses
Joshua Straquadine: Evolution of the charge density wave state in the rare-earth tritellurides under uniaxial stress and disorder Kyung-Yun Shin: Electronic Structure and Charge Density Waves in the Rare Earth (R) Tellurides RTe₂ and R₂Te₅ Nancy Ru: Charge density wave formation in rare earth tritellurides
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Fisher Research Group
Geballe Laboratory for Advanced Materials
Dept. of Applied Physics
Stanford University
CA 94305-4045

Last Updated: May 25th 2022

Research: Charge Density Waves