Cryogenic environment enables strong strain tuning of excitons in ZrSe3

Straintronics is turning mechanical deformation into a switch for controlling the optical and electronic behavior of advanced layered materials. By stretching or compressing a crystal, researchers can reshape its band structure and, in turn, tune excitons—electron–hole bound states that dominate optical spectra in semiconductors. Layered ZrSe₃, notable for its in-plane anisotropy, has now been highlighted as a particularly responsive platform for next-generation strain-enabled devices.

In a new study, a physics team led by Baoli Liu at the Institute of Physics, Chinese Academy of Sciences, investigates how cryogenic biaxial compression modulates excitons in multilayer ZrSe₃. The work focuses on a key challenge for practical optics and sensing: obtaining a large, controllable optical response from manageable strain engineering strategies, especially under environmentally constrained conditions.

The researchers implemented a temperature-driven approach to generate biaxial compressive strain. ZrSe₃ flakes were carefully transferred onto a flexible polycarbonate substrate, and then the system was cooled to cryogenic temperatures. As the polycarbonate contracted, it imposed compressive strain on the attached ZrSe₃, enabling strain transfer without mechanical fixtures that could complicate device integration.

To read out the optical consequences of this strain, they employed differential reflectance spectroscopy across various temperatures. The spectra revealed a striking redshift of excitonic resonances, demonstrating that exciton energies in ZrSe₃ can be strongly shifted by the applied biaxial compression.

Quantitatively, the exciton energy shift corresponds to a gauge factor of approximately 136 meV/%—a magnitude described as comparable to the highest strain responses reported for two-dimensional materials. Such a large response implies unusually strong strain sensitivity of both excitonic transitions and the underlying band structure.

The study places ZrSe₃ within the broader context of group IV–V transition metal trichalcogenides, materials that have gained attention for their orientation-resolved strain response arising from reduced in-plane symmetry. Earlier results showed substantial gauge factors under uniaxial tension; here, the team extends the concept by demonstrating that biaxial strain can be even more effective for exciton modulation.

Beyond reporting a strong effect, the findings emphasize the practicality of temperature-assisted strain control for flexible optoelectronics. With excitons acting as a direct bridge between strain and optical signals, the approach offers a route toward strain-tunable photodetectors and other wearable or stretchable sensing technologies.

The publication appears in Nano Research on May 12, 2026. The authors expect the results to advance band structure engineering in anisotropic 2D semiconductors and to accelerate research toward viral “strain-to-light” device concepts.

The team acknowledges contributions from researchers including Hao Li, Yu Hua, Jiaru Zhou, Geng Li, Changzhi Gu, Gang Wang, and Xiaofeng Fan. Financial support was provided by multiple Chinese national and institutional programs, including key national research funding and foundational science initiatives.

Keywords

Straintronics; ZrSe₃; excitons; biaxial compression; cryogenic environment; differential reflectance spectroscopy; gauge factor; flexible optoelectronics; 2D anisotropic semiconductors; photodetectors