Ultrafast Optical Control of Magnetic Order and Fermi Surface Topology at a Quantum Critical Point*

Designing material properties on demand has important implications to future technological applications. Although it is theoretically possible to tune various intrinsic competing interactions, there are fundamental limitations to this approach for quantum materials at equilibrium. In recent years, ultrafast spectroscopy has evolved as a promising tool to use light to dynamically induce non-trivial electronic states of matter. Here  we investigate light pulse driven dynamics in a heavy fermion system close to quantum criticality. We show, with a minimal Kondo lattice model, that light can de-hybridize the local Kondo screening and induce magnetic order out of a previously paramagnetic state. Depending on the laser pulse field parameters, it is possible to deconfine the Kondo singlet and thereby induce second order phase transition to a dynamically ordered state, as well as a dynamical Lifshitz transition that changes the Fermi surface topology from hole- to electron-like. We also calculate a few experimental measurable quantities for verification.