Advances in Ultrafast Control and Probing of Correlated-Electron Materials

In this paper, we present recent results on ultrafast control and probing of strongly correlated-electron materials. We focus on magnetoresistive manganites, applying excitation and probing wavelengths that cover the mid-IR to the soft X-rays. In analogy with near-equilibrium “filling” and “bandwidth” control of phase transitions, our approach uses both visible and mid-IR pulses to stimulate the dynamics by exciting either charges across electronic bandgaps or specific vibrational resonances. X-rays are used to unambiguously measure the microscopic electronic, orbital, and structural dynamics. Our experiments dissect and separate the nonequilibrium physics of these compounds, revealing the complex interplay and evolution of spin, lattice, charge, and orbital degrees of freedoms in the time domain.