Scientists at the National Synchrotron Light Source II (NSLS-II) have demonstrated a method for instantly transforming an electrical insulator into a conductor using light, a feat accomplished with laser pulses lasting just 100 femtoseconds, or one hundred quadrillionths of a second. The research, focused on magnetoresistive manganites, reveals a previously inaccessible phase of matter and offers new insights into controlling materials for future technologies. “The switching mechanism is really fast, much faster than any electronic devices we have today,” said Jonathan Pelliciari, a beamline scientist at the Soft Inelastic X-ray Scattering (SIX) beamline. By employing X-ray techniques at the SIX beamline, the team observed how light drives the material into this conductive state, which persists even after the laser pulse ends, suggesting potential applications in data storage and quantum computing.
Magnetoresistive Manganites Triggered by Ultrafast Laser Pulses
Magnetoresistive manganites, a unique class of quantum materials, respond rapidly to external stimuli; researchers have now shown they can be switched between conductive and insulating states using only light. This methodology bypasses traditional methods requiring electrodes or electrical currents, relying instead on the energy delivered by photons to alter the material’s properties. These investigations revealed the creation of a previously inaccessible phase, a nonthermal conductive state not achievable through conventional heating techniques. This induced state isn’t fleeting, persisting even after the laser pulse ceases, suggesting a fundamental stability. Shiyu Fan, a beamline scientist at the Inelastic X-ray Scattering (IXS) beamline and lead author of the work, noted that light offers a more direct and selective way to switch a quantum material than conventional approaches based on thermal cycling or static electric and magnetic fields. This ability to control a material’s phase while preserving its quantum characteristics holds promise for future quantum-device design and data storage applications, potentially encoding information in distinct, light-activated physical states.
Instead of simply warming the sample, the laser can drive the system into a distinct nonthermal state.
Shiyu Fan, a beamline scientist at the Inelastic X-ray Scattering (IXS) beamline and lead author of this work
RIXS and XAS Reveal Nonthermal Conductive Phase
To understand how this transformation occurs at the microscopic level, they leveraged resonant inelastic X-ray scattering (RIXS) and X-ray absorption spectroscopy (XAS) at the SIX beamline, alongside in-situ transport measurements. This persistence opens possibilities for data storage and quantum computing applications, where stable, switchable physical states are essential. The integration of advanced laser systems across multiple NSLS-II beamlines is proving vital, allowing for a broad range of time-resolved measurements and complementing research conducted at facilities specializing in even shorter-lived states.
The switching mechanism is really fast, much faster than any electronic devices we have today.
Jonathan Pelliciari, a beamline scientist at the Soft Inelastic X-ray Scattering (SIX) beamline
Persistent Hidden Phase Enables Potential Data Storage
The team, led by scientists like Jonathan Pelliciari, demonstrated the ability to switch these materials from insulating to conductive states using laser pulses lasting only 100 femtoseconds, a timeframe significantly faster than current electronic devices. This rapid transition isn’t achieved through traditional means; instead of electrodes or electrical currents, the process relies solely on light. “Once you switch the material, it keeps the same state for a while until another external stimulus is applied to revert it back,” explains Pelliciari, highlighting the potential for encoding information. While current systems require heating to reset the material, ongoing research aims to achieve full control through light-driven manipulation, bringing fully controllable devices closer to reality.
The ability to control a material’s phase while preserving its correlated quantum character could be important for future quantum-device design.
Shiyu Fan, a beamline scientist at the Inelastic X-ray Scattering (IXS) beamline and lead author of this work
Researchers are now leveraging this capability to not only induce previously inaccessible phases in materials, but also to meticulously characterize their behavior with unprecedented detail. A portable ultrafast laser system, capable of delivering pulses lasting just 100 femtoseconds, is central to this advancement, allowing for shared access across experimental stations and broadening the scope of time-resolved measurements. Beyond the discovery of a phase, the system’s versatility is proving invaluable.
