Engineering Robust Strain Transmission in van der Waals Heterostructure Devices

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Atomically thin van der Waals materials offer tunable quantum properties.
• Strain is a key tuning parameter, but standard device components like graphite and hexagonal boron nitride (hBN) exhibit poor strain transfer.
• This limitation hinders high-strain experiments in van der Waals heterostructures.

Purpose of the Study:

• To investigate strain transmission in less-explored orthorhombic crystals.
• To assess the feasibility of using these crystals for high-strain applications at cryogenic temperatures.
• To demonstrate efficient strain transfer to other 2D materials within heterostructures.

Main Methods:

• Experimental investigation of strain transmission in orthorhombic crystals.
• Cryogenic temperature measurements to evaluate strain robustness.
• Fabrication of heterostructure devices incorporating orthorhombic crystals and 2D materials.
• In situ optical property measurements of monolayer WS₂ under strain and gate control.

Main Results:

• Orthorhombic crystals demonstrate robust strain transmission up to several percent at cryogenic temperatures.
• Efficient strain transfer from orthorhombic crystals to other 2D materials in heterostructures was achieved.
• Demonstrated simultaneous in situ strain and gate control of monolayer WS₂ optical properties using Bi₂SeO₅ as a substrate.

Conclusions:

• Orthorhombic crystals overcome the strain transfer limitations of traditional van der Waals materials.
• This approach enables combined cryo-strain and gate tuning for diverse layered quantum systems.
• Opens new avenues for exploring moiré heterostructures, 2D magnets, superconductors, and gated 2D devices.