How to make a material more correlated with light

From top to bottom, electronic spectra show more and more coherence-incoherence spectral weight transfer, indicative of enhanced electron-lattice coupling in the strongly driven system.

Our preprint “Light-enhanced electron-phonon coupling from nonlinear electron-phonon coupling” is available on arXiv. In this work, it is shown how one can amplify electron-lattice coupling by using lasers that are tuned to a phonon, that is coupled quadratically to the electrons of the material. Such enhanced electron-lattice coupling can lead to the formation of polarons – electrons coupled to a “cloud” of lattice distortion – or even make the system superconducting. It has recently been debated how possible light-induced superconductivity in carbon football molecular crystal (“fullerenes”) may come about, and nonlinear electron-phonon coupling might play an important role. Similarly, more direct signatures of light-enhanced electron-lattice coupling have been observed in metallic bilayers of the carbon flatland material graphene. Now experiments have to be performed to check the hypothesis of our theory paper.

Elementary-particle physics in laser-driven materials

Dancing Weyl cones: When excited by tailored laser pulses (white spiral), the cones in a Dirac fermion material dance on a path (8-shape) that can be controlled by the laser light. This turns a Dirac material into a Weyl material, changing the nature of the quasiparticles in it. One of the cones hosts right-handed Weyl fermions; the other cone hosts left-handed ones. [less] © Jörg M. Harms/MPSD
Dancing Weyl cones: When excited by tailored laser pulses (white spiral), the cones in a Dirac fermion material dance on a path (8-shape) that can be controlled by the laser light. This turns a Dirac material into a Weyl material, changing the nature of the quasiparticles in it. One of the cones hosts right-handed Weyl fermions; the other cone hosts left-handed ones. © Jörg M. Harms/MPSD

Our work “Creating stable Floquet-Weyl semimetals by laser-driving of 3D Dirac materials” was published in Nature Communications (doi:10.1038/ncomms13940).

Further reading:
Studying fundamental particles in materials