Photon-Electron Interactions in Dirac Quantum Materials
- Univ. of Washington, Seattle, WA (United States). Dept. of Material Science and Engineering
The objective of this proposal was to explore the fundamental light-matter interactions in a new class of Dirac quantum materials, atomically thin transition metal dichalcogenides (TMDs). Monolayer TMDs are newly discovered two-dimensional semiconductors with direct bandgap. Due to their hexagonal lattice structure, the band edge localizes at corner of Brillouin zone, i.e. “Dirac valleys”. This gives the corresponding electron states a “valley index” (or pseudospin) in addition to the real spin. Remarkably, the valley pseudospins have circularly polarized optical selection rules, providing the first solid state system for dynamic control of the valley degree of freedom. During this award, we have developed a suite of advanced nano-optical spectroscopy tools in the investigation and manipulation of charge, spin, and valley degrees of freedom in monolayer semiconductors. Emerging physical phenomena, such as quantum coherence between valley pseudospins, have been demonstrated for the first time in solids. In addition to monolayers, we have developed a framework in engineering, formulating, and understanding valley pseudospin physics in 2D heterostructures formed by different monolayer semiconductors. We demonstrated long-lived valley-polarized interlayer excitons with valley-dependent many-body interaction effects. These works push the research frontier in understanding the light-matter interactions in atomically-thin quantum materials for protentional transformative energy technologies.
- Research Organization:
- Univ. of Washington, Seattle, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
- DOE Contract Number:
- SC0008145
- OSTI ID:
- 1408272
- Report Number(s):
- DoE-UW-SC-0008145
- Country of Publication:
- United States
- Language:
- English
Similar Records
Colloquium: Excitons in atomically thin transition metal dichalcogenides
Magnetic control of valley pseudospin in monolayer WSe2