AEP Faculty Candidate Seminar: Ankit Disa
“NON-EQUILIBRIUM CONTROL OF QUANTUM MATERIALS WITH LIGHT”
Dr. Ankit Disa
Humboldt Postdoctoral Research Fellow, Max Planck Institute for the Structure and Dynamics of Matter
Quantum materials exhibit unique macroscopic phenomena with enormous technological potential, ranging from high-temperature superconductivity to topologically protected transport. Hence, at the forefront of condensed matter research is the goal of understanding and controlling their emergent behavior at the smallest length and time scales possible. Due to the strongly intertwined nature of electrons and the crystal lattice in these materials, manipulating the atomic structure allows one to tune interactions and create novel electronic and magnetic phases. In this talk, I will describe how light can be used to engineer structural distortions in quantum materials on ultrafast time scales, providing a powerful pathway to realize non-equilibrium states of matter, often with functionalities not accessible otherwise. First, I will illustrate the application of this approach to the antiferromagnet CoF 2 . By resonantly exciting optical phonons at terahertz frequencies, a ferrimagnetic phase transition can be driven with light, whose induced magnetization is 100-fold larger than the equilibrium limit. Second, I will demonstrate that the coupling of optically driven phonons to long-wavelength strain leads to a metastable ferroelectricity in the quantum paraelectric SrTiO 3 . In this case, the symmetry-broken state remains for hours after excitation. These experiments provide a basis for the rational design of non-equilibrium functionalities. Integrated with targeted materials synthesis, such control promises to unlock new physical phenomena and enable next-generation quantum and ultrafast technologies.
Meeting ID: 970 8523 6155