Quantum sculpting for future electronics

An international team led by researchers from the University of Geneva (UNIGE), including researchers from the universities of Salerno, Utrecht and Delft, has designed a material in which the dynamics of electrons can be controlled by curving the fabric of space in which they evolve. These properties are of interest for next-generation electronic devices, including the optoelectronics of the future. The research findings were published in the journal Nature Materials.

The telecommunications of the future will require new, powerful electronic devices that are capable of processing electromagnetic signals at unprecedented speeds, in the picosecond range (one thousandth of a billionth of a second). This is unthinkable with current semiconductor materials, such as silicon, which is widely used in the electronic components of telephones, computers and game consoles. To achieve this, scientists and industry are focusing on the design of new quantum materials.

Due to their unique properties — especially the collective reactions of the electrons that compose them — these quantum materials could be used to capture, manipulate and transmit information-carrying signals (for example photons, in the case of quantum telecommunications) within new electronic devices. They can also operate in electromagnetic frequency ranges that have not yet been explored and would thus open the way to high-speed communication systems.

Andrea Caviglia, a professor at the Department of Quantum Matter Physics in the Faculty of Science of the UNIGE, said one of the most fascinating properties of quantum matter is that electrons can evolve in a curved space. ‘‘The force fields, due to this distortion of the space inhabited by the electrons, generate dynamics totally absent in conventional materials. This is an outstanding application of the principle of quantum superposition,’’ Caviglia said.

After an initial theoretical study, the international team of researchers designed a material in which the curvature of the space fabric is controllable. ‘‘We have designed an interface hosting an extremely thin layer of free electrons. It is sandwiched between strontium titanate and lanthanum aluminate, which are two insulating oxides,’’ said Carmine Ortix, professor at the University of Salerno.

This combination allowed the researchers to obtain particular electronic geometrical configurations which can be controlled on-demand. To achieve this, the research team used an advanced system for fabricating materials on an atomic scale. Using laser pulses, each layer of atoms was stacked one after another. This method allowed researchers to create special combinations of atoms in space that affect the behaviour of the material.

While the prospect of technological use is still far off, this new material opens up avenues in the exploration of very high-speed electromagnetic signal manipulation. These results can also be used to develop new sensors. The research team will further observe how this material reacts to high electromagnetic frequencies to determine its potential applications.

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