Overview
In a breakthrough study from Kiel University, researchers demonstrate a new way to control electrons in graphene using ultrashort laser pulses. For the first time, Dr. Jan-Philip Joost and Professor Michael Bonitz show that light pulses can induce electrons at highly specific locations within graphene, a single-atom-thick sheet of carbon. By simulating laser interactions with small graphene clusters, the team reveals a spatially selective response that could pave the way for ultra-fast nanoelectronic components operating in the petahertz range.
Graphene has long been prized for its exceptional electronic properties, including high carrier mobility and unique topological states. The new work shows that, even in a chemically homogeneous material (carbon-only graphene), precise control over electron positions is possible through the timing, strength, and sequence of ultrafast optical pulses. This challenges the conventional view that selective excitation requires molecules with different atoms and absorption properties.
How the study works
Simulation approach
The researchers explored the dynamics of electrons in tiny graphene clusters subjected to ultrashort laser pulses. By adjusting pulse parameters, they tracked how electrons migrate and localize, revealing predictable patterns of accumulation at designated edges or sites within femtoseconds. As the pulses strike the graphene cluster, electrons are drawn toward one edge; a subsequent pulse can generate electrons almost instantaneously at another site. This enables a form of optical steering, acting like a traffic signal that directs electron flow on the nanoscale.
Spatial selectivity in a homogeneous lattice
“We discovered this spatial selectivity in a chemically completely homogeneous material – graphene consists solely of carbon,” Bonitz explains. “Until now, such an effect was only known in molecules composed of different atoms with distinct absorption properties. In our graphene clusters, control emerges solely from the electronic structure and from special topological states. Even under small perturbations, the electron positions remain stable, making the control reliable.”
Why this matters
The finding has potential implications for the next generation of electronics. Today’s transistors operate in the gigahertz range, but laser-pulse-driven graphene components could, in principle, function in the petahertz range—up to 10,000 times faster. The ability to guide electrons to precise locations could enable rapid, low-energy data transport and processing, with significant impact on high-performance computing, AI accelerators, and advanced communication systems.
Applications, challenges and next steps
Precisely steered electron pathways in graphene could lead to ultra-fast interconnects, logic elements, and switchable regions within a single graphene sheet. In communication systems, this could translate into faster data rates with reduced energy consumption, opening doors to compact, graphene-based nanochips and photonic-electronic hybrids. However, translating the observed spatial selectivity from simulated clusters to real devices remains a major challenge. Engineers will need to demonstrate reliable control in scalable architectures, ensure repeatable qubit-like states, and integrate these excited electrons into functional circuits without degradation of coherence or stability.
Joost emphasizes the practical horizon: “If these processes can be transferred into real devices, it would be a huge leap for nanoelectronics.” The path forward involves refining laser control on femtosecond timescales, understanding interaction with the surrounding circuitry, and developing robust fabrication methods to harness the technique in macroscopic graphene-based components.
Looking ahead
The study adds a new dimension to graphene research, suggesting that ultrafast photonic control can sculpt electronic landscapes in a material known for its plain, carbon-only composition. As researchers push beyond clusters toward integrated devices, the prospect of petahertz electronics—relying on light-driven, location-specific electron manipulation—becomes an intriguing target for nanoelectronics, photonics, and quantum-inspired computing technologies.
