Ultrafast atomic-scale imaging and control of nonequilibrium phenomena in quantum materials

Introduction

Quantum materials (QMs) are of great importance for the development of future quantum nanophotonics and nanoelectronic devices. To harness their full potential and design novel functionalities, it is essential to understand how their macroscopic quantum states arise from the microscopic interaction between their charge, lattice, orbital, and spin degrees of freedom, and how they respond to external perturbations.

Limitations of Current Techniques

While ultrafast techniques offer unique insight into microscopic interactions at global, macroscopic scales, they fall short of capturing the local response of a many-body quantum state directly at the atomic scale.

Advantages of Scanning Tunneling Microscopy

In contrast, scanning tunneling microscopy (STM) enables imaging of stationary quantum states with angstrom spatial resolution. This technique reveals:

• Atomic inhomogeneities
• Local disorder
• Variations of quantum phases over angstrom scales

Such irregularities are ubiquitous in real devices and can even be a key feature of technically relevant metastable phases. In these cases, the global understanding of the nonequilibrium response of a quantum state is not sufficient to fully capture its properties. One must also understand the localized response directly at the relevant spatial - angstrom - scales. Yet, the study of atomically localized nonequilibrium dynamics in QMs has so far been out of reach.

Proposal Overview

In this proposal, I will employ ultrafast Terahertz-lightwave-driven STM (THz-STM) to:

1. Explore the response of correlated electron states to global and local perturbations and as a function of their local environment.
2. Induce new quantum properties by periodic driving with light to create Floquet topological states and study their topological properties at the atomic scale.

Conclusion

FASTOMIC will bridge the gap between atomic real-space and ultrafast real-time investigation of condensed quantum matter, providing scientific insights and technological advances that go significantly beyond existing capabilities.