Realizing Novel Phases of Materials with Light-Matter Interaction
Abstract
Major Goals: In this project, we investigated controlling the properties of materials by simply shining light onto them. This is based on the fact that, if the energy of the incident light is below the absorption threshold, one will not have direct absorption making it possible to observe coherent phenomenon. In this case, electrons and photons can coherently hybridize forming so-called Floquet-Bloch states. Our goal is to use these Floquet-Bloch states to engineer materials with distinct properties. By tuning the properties of the incident light (such as fluence, frequency or polarization), one can change the resultant material properties. Our goal was to establish Floquet-Bloch states in systems other than topological insulators and study their formation and decay dynamics in these different material systems. The plan was then to investigate using Floquet-Bloch states to both engineer new phases of matter and to change the properties of existing materials. Examples are light induced quantum anomalous phase in graphene and optical modification of the exchange interaction in Mott insulators using the Floquet-Bloch states. Accomplishments: During the grant period, we have made significant advances in multiple directions. First, we have greatly improved capabilities of time and angle resolved photoemission spectroscopy (tr-ARPES). We can now reliably perform tr-ARPES using 11 eV, 18, 26 or 31 eV at a very high repetition rate of 300 kHz. Our energy resolution is also one of the best in the world (16 meV at 11 eV and 30 meV at 30 eV). These development are absolutely key in detecting the electronic band dispersion of light induced exotic phases. Secondly, we achieved distinguishing Floquet-Bloch (FB) and Volkov states in a systematic manner in Bi2Se3. This will enable selective study of FB states in tr-ARPES in different systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 31, 2021
- Accession Number
- AD1186509
Entities
People
- Nuh Gedik
Organizations
- Massachusetts Institute of Technology