https://cdn.gophotonics.com/news/csm_2024_IntiSodemann_Photo_1_Likun_Shi_left_and_Inti_Sodemann_right_at_work_61c3b0257d_638523843866487095.jpg712370

A team of scientists from Leipzig University and Nanyang Technological University in Singapore have proven that certain materials, previously thought to be completely transparent to specific light frequencies, can still generate electrical currents when exposed to light. This discovery challenges long-held assumptions in the field of materials science.

Inti Sodemann Villadiego, Professor at the Institute of Theoretical Physics at Leipzig University and his colleagues investigated what are known as “Floquet Fermi liquid” states. A Fermi liquid is a special state of many quantum mechanical particles with properties that can be very different from those of ordinary classical liquids such as water at ambient temperature.

Fermi liquids can arise in a wide variety of situations, from common materials such as the electrical fluid of electrons in metals like gold or silver, to more exotic situations such as the fluid of Helium-3 atoms at low temperatures. They can display “spectacular properties”, such as becoming superconductors of electricity at low temperatures. The “Floquet Fermi liquid” is a variant of this state realised when the particles of the fluid are periodically shaken, such as what happens to electrons in metals when they are illuminated by ideally periodic light.

“This opens new paradigms for constructing opto-electronic and photovoltaic devices, such as light amplifiers, sensors and solar cells,” says Inti Sodemann Villadiego. “In our publication, we explain several properties of these fluid states. To study them, we had to develop detailed theoretical models of complex states of electrons shaken by light, which is far from easy.” After the publication in Physical Review Letters, the four researchers – including Sodemann Villadiego from Leipzig University and his colleague Li-kun Shi – received a special honour.

Click here to read the paper titled, "Floquet Fermi Liquid".