Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                

Anharmonic order-parameter oscillations and lattice coupling in strongly driven 1 T−TaS2 and TbTe3 charge-density-wave compounds: A multiple-pulse femtosecond laser spectroscopy study

P. Kusar, T. Mertelj, V. V. Kabanov, J.-H. Chu, I. R. Fisher, H. Berger, L. Forró, and D. Mihailovic
Phys. Rev. B 83, 035104 – Published 10 January 2011
PDFHTMLExport Citation
Abstract
Authors
Article Text
  • INTRODUCTION
  • EXPERIMENTAL
  • RESULTS
  • DISCUSSION
  • CONCLUSIONS
  • ACKNOWLEDGEMENTS
    • References

    Abstract

    The anharmonic response of charge-density wave (CDW) order to strong laser-pulse perturbations in 1 T−TaS2 and TbTe3 is investigated by means of multiple-pump-pulse time-resolved femtosecond optical spectroscopy. We observe remarkable anharmonic effects hitherto undetected in systems exhibiting collective charge ordering. The efficiency for additional excitation of the amplitude mode by a laser pulse becomes periodically modulated after the mode is strongly excited into a coherently oscillating state. A similar effect is observed also for some other phonons, where the cross-modulation at the amplitude-mode frequency indicates anharmonic interaction of those phonons with the amplitude mode. By analyzing the observed phenomena in the framework of time-dependent Ginzburg-Landau theory we attribute the effects to the anharmonicity of the mode potentials inherent in the broken symmetry state of the CDW systems.

    • Figure
    • Figure
    • Figure
    • Figure
    • Received 8 October 2010

    DOI:https://doi.org/10.1103/PhysRevB.83.035104

    © 2011 American Physical Society

    Authors & Affiliations

    P. Kusar1, T. Mertelj1, V. V. Kabanov1, J.-H. Chu2, I. R. Fisher2, H. Berger3, L. Forró3, and D. Mihailovic1

    • 1Complex Matter Department, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
    • 2Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, California 94304, USA
    • 3Physics Department, École Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland

    Article Text (Subscription Required)

    Click to Expand

    References (Subscription Required)

    Click to Expand
    Issue

    Vol. 83, Iss. 3 — 1 January 2011

    Reuse & Permissions
    Access Options
    Author publication services for translation and copyediting assistance advertisement

    Authorization Required

    Log In
    Other Options
    ×

    Images

    • Figure 1
      Figure 1
      ΔR/R transients as a function of t12 in 1 T−TaS2 (a) in the UDPP configuration shown in the schematics (b); L = lens, S = sample, C = chopper, H.D. = homodyne detection system. For comparison, ΔR/R transients in the SDPP configuration are shown in (c). The lower graphs show UDPP power spectra in 1 T−TaS2 around the fundamental frequency of the strongest mode (d) and around the second harmonic of the fundamental frequency (e). The thin curve in (d) and (e) is the standard single-pump-pulse spectrum.Reuse & Permissions
    • Figure 2
      Figure 2
      Spectra of the strongest mode (a), (b), and weaker modes (d), (e), as functions of t12 in the UDPP configuration at different intensities of the P1 pulse train in 1 T−TaS2. For comparison the low-excitation SDPP-configuration spectra are shown in (c) and (f).Reuse & Permissions
    • Figure 3
      Figure 3
      Integrated intensities of the strongest modes as functions of t12 in UDPP configuration (a) at I1=4×I2 in 1 T−TaS2 and (c) at I1=2.4×I2 in TbTe3. Normalized power spectra of the traces are shown in panels (b) and (d). Open symbols correspond to the low-intensity SDPP response. Note the difference in the modulation frequency for the 3.38-THz mode in 1T−TaS2 (b) and the 2.63-THz mode in TbTe3 (d) between the UDPP (full triangles) and SDPP (open triangles) cases.Reuse & Permissions
    • Figure 4
      Figure 4
      (a) Orbits of Eq. (2) in the phase space in the absence of damping (γ=0). The long arrow represents the initial excitation by the P1 pulse. The short arrows represent the additional excitation by the P2 pulse, which transfers the system to different orbits depending on t12. Simulated power spectrum as a function of t12 in the absence of damping is shown in (b); with damping (γ=0.01) and short excitation pulses, ω0τg=0.2π, (c); with damping and long excitation pulses ω0τg=2π, (d); with damping, long excitation pulses, and a finite laser penetration depth, λ/ξ=16, (e).Reuse & Permissions
    ×

    Sign up to receive regular email alerts from Physical Review B

    Log In

    Cancel
    ×

    Search

    Article Lookup

    Paste a citation or DOI
    Enter a citation
    ×