Condensed-Matter Physics & Materials Science Seminar

In this talk I will discuss some of our recent work aimed at controlling the properties of quantum condensed matter with light. The main focus of the talk will be on the use of strong field coherent THz pulses to control complex oxides, especially High-Tc cuprates. The novelty of this class of ultrafast THz control experiments is that unlike all previous attempts to guide the macroscopic properties of matter with light, our approach acts directly on the important low energy degrees of freedom, without exciting incoherent hot electrons. For example we have shown that the crystal lattice of a complex oxide can be deformed coherently by exciting infrared active vibrational modes. By these means we have shown how insulator metal transitions and magnetic transitions can be controlled on the ultrafast timescale.
The most striking recent result includes the generation of a non-equilibrium superconducting state in YBCO at room temperature.
Due to the short lengthscales and the fast timescales involved in condensed matter, femtosecond x-ray scattering and spectroscopy experiments with Free Electron Lasers are necessary to interrogate the microscopic non-equilibrium paths. The talk will cover some of the first experiments.