Cornell Engineers Use Ultrafast Light to Control Atomic-Scale Material Expansion

Edited by: Vera Mo

Cornell Engineering researchers have developed a novel method to manipulate material properties using ultrafast pulses of low-frequency infrared light. This technique induces rapid atomic-scale expansion and contraction within a material's lattice, a phenomenon termed a strain-driven "breathing" effect. This controlled "breathing" holds the potential to quickly activate or deactivate a material's electronic, magnetic, or optical properties.

The findings, published on September 12, 2025, in Physical Review Letters, were co-led by Jakob Gollwitzer and Jeffrey Kaaret. The research team, including Associate Professors Nicole Benedek and Andrej Singer, explored light-based manipulation of material properties, a less common approach compared to traditional mechanical strain techniques. Benedek's theoretical work was crucial in predicting the optimal light frequencies and experimental parameters for achieving "dynamic" strain, a temporary, reversible shape change that differs from static strain.

Lanthanum aluminate was chosen for the study due to its simple structure and minimal intrinsic properties, serving as an ideal substrate for investigating light-induced strain. The researchers used picosecond bursts of terahertz light to excite specific atomic motions, resulting in a rapid expansion of the material's lattice. Notably, this process not only induced the intended strain but also led to a permanent improvement in the material's crystalline structure, creating a more ordered state. This unexpected structural enhancement through light interaction opens new avenues for material refinement.

This advancement in controlling material properties with light could accelerate progress in various technological fields, including the development of ultrafast switches, tunable superconductors, and advanced dynamic sensors. Understanding light's interaction with complex oxide materials enables scientists to access properties not achievable through conventional methods. The research received support from the Department of Energy's Office of Basic Energy Sciences and the Cornell Center for Materials Research, funded by the National Science Foundation's MRSEC program.

Beyond this specific research, ultrafast lasers are broadly recognized for their transformative applications in materials science. Operating in the femtosecond to picosecond range, these lasers enable high-precision micro-machining with minimal thermal diffusion, facilitating intricate fabrication processes for components in microelectronics and semiconductor manufacturing. The capacity of terahertz radiation to manipulate matter is also a significant area of scientific inquiry, with strong-field terahertz pulses demonstrating the ability to engineer novel dynamic states within materials by influencing their intrinsic fields. This capability extends to controlling lattice geometry, which in turn affects magnetic order, superconductivity, and ferroelectric polarization. The Cornell team's work aligns with these broader trends, offering a sophisticated method for light-driven material control and property modulation.

Sources

  • Phys.org

  • Cornell Chronicle

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