Abstract
Spin-flip dark excitons are optical-dipole-forbidden quasiparticles with remarkable potential in optoelectronics, especially when they are realized within cleavable van der Waals materials. Despite this potential, dark excitons have not yet been definitively identified in ferromagnetic van der Waals materials. Here, we report two dark excitons in a model ferromagnetic material CrI3 using high-resolution resonant inelastic x-ray scattering and show that they feature narrower linewidths compared to the bright excitons previously reported in this material. These excitons are shown to have spin-flip character, to disperse as a function of momentum, and to change through the ferromagnetic transition temperature. Given the versatility of van der Waals materials, these excitons hold promise for new types of magneto-optical functionality.
| Original language | English |
|---|---|
| Article number | 011042 |
| Journal | Physical Review X |
| Volume | 15 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2025 |
Funding
Work performed at Brookhaven National Laboratory and Harvard University was supported by the U.S. Department of Energy (DOE), Division of Materials Science, under Contract No. DE-SC0012704. Work performed at the University of Texas at Austin was supported by the United States Army Research Office (W911NF-23-1-0394) (F.\u2009B.) and the National Science Foundation under the NSF CAREER Award No. 2441874 (E.\u2009B.). F.\u2009B. acknowledges additional support from the Swiss NSF under fellowship No. P500PT_214437. S.\u2009J. was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Grant No. DE-SC0022311. Part of this research (T.\u2009B.) was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. The work by J.\u2009W.\u2009V. is supported by the Quantum Science Center (QSC), a National Quantum Information Science Research Center of DOE. Crystal growth at ORNL as supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Material Science and Engineering Division. This research used beamline 2-ID of the National Synchrotron Light Source II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. We also acknowledge glovebox resources made available through BNL/LDRD No. 19-013. Work performed at Brookhaven National Laboratory and Harvard University was supported by the U.S. Department of Energy (DOE), Division of Materials Science, under Contract No. DE-SC0012704. Work performed at the University of Texas at Austin was supported by the United States Army Research Office (W911NF-23-1-0394) (F.B.) and the National Science Foundation under the NSF CAREER Award No. 2441874 (E.B.). F.B. acknowledges additional support from the Swiss NSF under fellowship No. P500PT_214437. S.J. was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Grant No. DE-SC0022311. Part of this research (T.B.) was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. The work by J.W.V. is supported by the Quantum Science Center (QSC), a National Quantum Information Science Research Center of DOE. Crystal growth at ORNL as supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Material Science and Engineering Division. This research used beamline 2-ID of the National Synchrotron Light Source II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. We also acknowledge glovebox resources made available through BNL/LDRD No. 19-013.