Investigating the role of band dispersion and topology in determining the properties of topological phases of matter
Abstract
We will study the interplay and role of the unique band dispersion, inversion and topology in topological materials with its low-energy fermion dynamics and develop new response functions as probes of their novel topological phases. We seek to obtain a deeper understanding of light-matter interactions in topological quantum materials by experimentally identifying new optical signatures and microscopically describing these interactions to explain the contribution from symmetry, chirality relations and other band features of these systems. We will design experiments to study and optically control photocurrents in topological materials, especially through systemically studying the frequency, intensity gradients and optical phase dependence of the nonlocal response from these systems at mid-infrared wavelengths. The experimental studies will be combined with the minimal model and first principles analyses to develop the photogalvanic effect as a powerful, table-top tool for determining band topology and shedding light on electron excitation and relaxation pathways in the momentum space. The detailed microscopic mechanisms will be explored to shed light upon the fundamental and underexplored features of these systems that can potentially be useful for mid-IR photodetectors with new functionalities such as sensitivity to photon spin, intensity and optical phase gradients. We will also attempt to understand how optical response of low energy quasiparticles in topological systems are fundamentally different from excitations in conventional systems. Understanding of light-matter interactions in topological materials may find applications in computing, photonics and sensing and will pave the way for novel devices enabled by active materials and new coupling mechanisms with robust functionalities, all relevant to the DoD’s vision for developing novel devices and systems with unprecedented response.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010345
Entities
People
- Ritesh Agarwal
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Pennsylvania