The charge-density-wave (CDW) instability in the underdoped, pseudogap part of the cuprate phase diagram has been a major recent research focus, yet measurements of dynamic, energy-resolved charge correlations are still in their infancy. As a result, our temperature-dependent measurements provide evidence for localized CDW formation above the bulk transition temperature T CDW. Furthermore, the wave vectors for the bidirectional order we observe differ from those theoretically predicted for checkerboard order competing with stripe order in a Fermi-surface nesting scenario, suggesting that factors beyond Fermi-surface nesting drive CDW order in TbTe 3. This indicates that similar driving mechanisms for CDW formation in the bulk, where anisotropic lattice strain energy is important, are at play at the surface. We more » propose that observation of two unidirectional CDW states indicates a decoupling of the surface Te layer from the rare-earth block layer below, and that strain variations in the Te surface layer drive the local CDW direction to the specific unidirectional or, in rare occurrences, bidirectional CDW orders observed. In addition, we find regions in which the bidirectional CDW states coexist. However, unlike previous STM measurements, and differing from measurements probing the bulk, we detect two perpendicular orientations for the unidirectional CDW with no directional preference for the in-plane crystal axes (a or c axis) and no noticeable difference in wave vector magnitude. Our measurements detect a unidirectional charge density wave (CDW) state in the surface Te layer with a wave vector consistent with that of the bulk q CDW = 0.30 ± 0.01c*. We studied TbTe 3 using scanning tunneling microscopy (STM) in the temperature range of 298–355 K. Scientific User Facilities Division OSTI Identifier: 1474140 Alternate Identifier(s): OSTI ID: 1469738 Grant/Contract Number: AC02-06CH11357 AC02-76SF00515 Resource Type: Accepted Manuscript Journal Name: Physical Review B Additional Journal Information: Journal Volume: 98 Journal Issue: 9 Journal ID: ISSN 2469-9950 Publisher: American Physical Society (APS) Country of Publication: United States Language: English Subject: 74 ATOMIC AND MOLECULAR = , Materials Sciences & Engineering Division Gordon and Betty Moore Foundation USDOE Office of Science (SC), Basic Energy Sciences (BES). (ANL), Argonne, IL (United States) Sponsoring Org.: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Publication Date: Wed Sep 12 00:00: Research Org.: Argonne National Lab. Stanford Univ., Stanford, CA (United States) SLAC National Accelerator Lab., Menlo Park, CA (United States).Stanford Univ., Stanford, CA (United States).Karlsruhe Institute of Technology, Karlsruhe (Germany).Karlsruhe Institute of Technology, Karlsruhe (Germany) Vienna Univ.Karlsruhe Institute of Technology, Karlsruhe (Germany) Delft Univ.Furthermore our results indicate that the low-temperature CDW order is not just the 90° rotated analogue of the one appearing at high temperatures. Surprisingly, these soft modes close to q CDW,2 = (0.68, 0, 0) show strong softening near T CDW,1 but do not exhibit any response to the lower-temperature transition at T CDW,2 = 68 K. In particular, we show that there are several phonon modes along both in-plane directions, which respond to the onset of the CDW transition at T CDW,1 = 308 K. Here, we report an inelastic x-ray scattering investigation of the lattice dynamics of DyTe 3.
PHONON DISPERSIO DAHED VERTICAL SERIES
What sets the heavier members of the RTe 3 series apart is the observation of a second CDW transition at lower temperatures having an in-plane ordering wavevector q CDW,2 || of almost the same magnitude but orthogonal to the ordering wavevector q CDW,1 || observed at higher temperatures. Similar to other CDW compounds, superconductivity is observed when the CDW order is suppressed via hydrostatic pressure. The phonon dispersion and thermodynamic properties of pyrope ( \(\hbox \).The family of rare-earth tritellurides RTe 3 features charge-density-wave (CDW) order related to strongly momentum-dependent electron-phonon coupling.