Microscopic description of displacive coherent phonons

  title={Microscopic description of displacive coherent phonons},
  author={Massil Lakehal and Indranil Paul},
  journal={Physical Review B},
We develop a Hamiltonian-based microscopic description of laser pump induced displacive coherent phonons. The theory captures the feedback of the phonon excitation upon the electronic fluid, which is missing in the state-of-the-art phenomenological formulation. We show that this feedback leads to chirping at short time scales, even if the phonon motion is harmonic. At long times this feedback appears as a finite phase in the oscillatory signal. We apply the theory to BaFe$_2$As$_2$, explain the… Expand
2 Citations

Figures from this paper

Strong self-trapping by deformation potential limits photovoltaic performance in bismuth double perovskite
The strong self-trapping in Cs2AgBiBr6 could impose intrinsic limitations for its application in photovoltaics, as well as being an indirect bandgap semiconductor. Expand
Detection of squeezed phonons in pump-probe spectroscopy
Robust engineering of phonon squeezed states in optically excited solids has emerged as a promising tool to control and manipulate their properties. However, in contrast to quantum optical systems,Expand


Observation of an amplitude collapse and revival of chirped coherent phonons in bismuth.
We have studied the A(1g) coherent phonons in bismuth generated by high fluence ultrashort laser pulses. We observed that the nonlinear regime, where the phonons' oscillation parameters depend onExpand
Coherent phonon coupling to individual Bloch states in photoexcited bismuth.
All the electronic states at the bismuth (111) surface display a photoinduced shift towards higher binding energy whose dynamics follows the evolution of the electronic temperature. Expand
Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation.
The time-resolved reflectivity in the intensely photoexcited Bi film is modulated by the coherent A(1g) phonon oscillation with a time-dependent oscillation period, which is attributed to an anharmonicity of the lattice potential. Expand
Impulsive Softening of Coherent Phonons in Tellurium.
It is demonstrated that coherent phonons allow monitoring the pathway to nonthermal laser-induced melting of crystalline materials and the observed frequency shift is of purely electronic origin. Expand
Displacive excitation of coherent phonons in YBa2Cu3O7.
We suggest a microscopic model that provides a consistent explanation of the recent femtosecond pump-probe experiments on YBa[sub 2]Cu[sub 3]O[sub 7], including the fact that the reflectivity changeExpand
Optical control of coherent optical phonons in bismuth films
Interference of impulsively excited coherent phonons in semimetals has been studied by using a double‐pulse pump–probe technique. Enhancement of the oscillation amplitude of an A1g mode is observedExpand
Phonon Driven Floquet Matter.
This work establishes that the recently demonstrated concept of light-induced nonequilibrium Floquet phases can also be applied when using coherent phonon modes for the dynamical control of material properties. Expand
Coherent Lattice Oscillations in Solids and Their Optical Control
Coherent optical phonons are the lattice atoms vibrating in phase with each other over a macroscopic spatial region. With sub-10 fs laser pulses, one can impulsively excite the coherent phonons of aExpand
Ultrafast Dynamics of photo-excited coherent phonons in Bi2Te3 thin-films
Nonequilibrium A1g longitudinal optical phonon with a frequency of 1.84THz in bismuth telluride (Bi2Te3) is coherently excited by ultrafast pulses. Time-resolved reflectivity measurements show aExpand
Localized vibrations in superconducting YBa2Cu3O7 revealed by ultrafast optical coherent spectroscopy
The interaction between phonons and high-energy excitations of electronic origin in cuprates and their role in the superconducting mechanisms is still controversial. Here we use coherent vibrationalExpand