Insider Brief
Berkeley Lab researchers observed a tunable Bose-Einstein condensate of excitons in an atomically thin semiconductor, creating a controllable platform for studying quantum fluids in solid materials.
The exciton condensate persisted up to about 2 Kelvin and could be tuned electrically, overcoming key limitations of short-lived, optically generated excitons.
Researchers found the condensate has multiple internal spin-valley structures that can be switched with a magnetic field, with potential applications in quantum simulation, optoelectronics and future superfluid-based devices.
PRESS RELEASE — Bose-Einstein Condensates (BECs) are often described as a “fifth state of matter”: a quantum state in which many particles lose their individual identities and behave as one collective object. For more than 60 years, researchers have sought to create such condensates from excitons — electron-hole pairs — as a solid-state route to macroscopic quantum coherence, which is useful for quantum technologies. This has been difficult to realize in controllable semiconductor devices because optically generated excitons have very short lifespans of around a billionth of a second, and BECs are normally attained with supercold gasses in a vacuum.
