The concept
Twist engineering is a method in materials science where the properties of a material are manipulated by changing the angle between layers of stacked two-dimensional materials, like graphene or other thin atomic layers.
By slightly rotating one layer relative to another, new and often surprising physical phenomena arise due to quantum mechanical interactions between the layers. This technique allows scientists to finely adjust the electronic, optical, and mechanical properties of materials, leading to the discovery of new phases of matter, such as superconductivity, and improving the control of light-matter interactions.
“Our findings highlight the remarkable potential of moiré superlattices to manipulate light-matter interactions at room temperature,” said Dr. Hanlin Fang, one of the leading authors of the study. “This could lead to significant advancements in the development of energy-efficient photonic devices.”
Key Findings
- Moiré Potential: We, for the first time, demonstrate the significance of moiré potential at room temperature due to atomic reconstruction, for example, featured as an unusually large twist-angle-dependent energy shift (>200 nm) of interlayer excitons.
- Enhanced Light Emission: a counterintuitive phenomenon arisen from the existence of moiré potential at room temperature is observed, that is, brighter excitons with longer lifetime.
- Device Applications: The integration of moiré superlattices with silicon single-mode cavities resulted in devices with significantly lower thresholds for light emission, one order of magnitude smaller compared to devices utilizing delocalized IXs.
Implications
This discovery opens new avenues for exploring many-body physics in moiré superlattices at elevated temperatures. It also suggests that these artificial quantum materials could be leveraged for advanced photonic and optoelectronic devices, including low-power lasers and other light-emitting technologies.
“With over a thousand 2D materials theoretically predicted, we can stack and twist them, providing countless opportunities to explore and manipulate new quantum materials with on-demand properties” says Dr. Sanshui Xiao, the project leader. “We are excited about the future applications of these materials”.
