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Nonlinear electron-phonon coupling in doped manganites

June 15, 2017

A new route to manipulate the electronic properties of a material via vibrational excitation

The control of material properties using ultrashort pulses of light is a promising route for the development of future electro-optical storage and high speed switching devices. One very fruitful approach is to use low energy excitations in the mid-infrared spectral range to realize the targeted changes [1,2]. The selectivity of the process minimizes the entropy added to the system as compared to the excitation of electronic transitions in the ultraviolet to near-infrared wavelengths range. In particular, the transient enhancement of superconductivity initiated via nonlinear phonon-phonon interactions is a nice example that has recently received large attention [3].
In this work, we report of a new route to manipulate the electronic properties of a material via vibrational excitation. Investigating the dynamics of the charge order in a manganites film following resonant excitation of a phonon mode to large amplitude, we find direct nonlinear coupling between the excited mode and the electronic degrees of freedom. In particular our work demonstrates that the nonlinear electron-phonon coupling is sufficiently strong to drive the insulator-metal transition in this material. The generalization of our approach leads to new ways of manipulating materials e.g. shaping their properties on ultrashort timescales.

[1] M. Rini, M. et al. Nature 449, 72–74 (2007)
[2] T. Kubacka, et al. Science 343, 1333–1336 (2014)
[3] R. Mankowsky, et al. Nature 516, 71–73 (2014)

Reference: V. Esposito, R. Mankowsky, M. Fechner, H. Lemke, M. Chollet, J. M. Glownia, M. Nakamura, M. Kawasaki, Y. Tokura, U. Staub, P. Beaud, and M. Först, Nonlinear electron-phonon coupling in doped manganites, Phys. Rev. Lett. 118, 247601 (2017). (10.1103/PhysRevLett.118.247601) Esposito-2017

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