Emergent Non-Equilibrium Phenomena in Driven Correlated Materials With Strong Spin Orbit Coupling
Abstract
Major Goals: The major goal of this project was to theoretically investigate out-of-equilibrium quantum many particle systems that have strong spin-orbit coupling. Particular emphasis was placed on systems with strong correlations. These investigations were carried out with the ultimate aim of finding out-of-equilibrium regimes with interesting properties that might be exploited in applications for the ARO, and DoD more generally. Important progress was made in this direction. Two examples of out-of-equilibrium regimes with interesting properties are Floquet (periodically driven) systems and pre-thermalized states following a quench to a new Hamiltonian. Both regimes are inherently non-equilibrium and have properties that are quasi-steady state. In a Floquet system, the time averaged (over one period) properties are independent of time, and in the pre-thermalized state there is a time-window of weak time dependence before the system begins to converge more rapidly to a thermal (equilibrium) state. In addition to these two scenarios, we also investigated a quench to a Floquet state: A system initially in equilibrium is suddenly subjected to a periodic drive. This third scenario is a combination of the first two. It turns out (theoretically) that one can obtain an approximate *time- independent* Hamiltonian that describes the dynamics for short-to-intermediate times after the quench to the periodic drive. This observation opens new possibilities for "Hamiltonian engineering" in solid-state systems, and may allow new physical regimes to be opened, possibly in "conventional materials" that are well-known and used in existing applications. To this end, we developed a "flow equation approach" based on renormalization group ideas to obtain such a time-independent effective Hamiltonian.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 2018
- Accession Number
- AD1081280
Entities
People
- Gregory A. Fiete
Organizations
- University of Texas at Austin