An international team whose research was coordinated by Osaka Metropolitan University (OMU) has reported the survival of metallic behavior in the strongly correlated molecular material ytterbium cesium fulleride (Yb₂CsC₆₀). The electrons in the newly synthesized material remained mobile and continued to conduct electricity even at the lowest temperatures studied, despite strong electron interactions that would normally be expected to drive the material into an insulating state.

The findings were published in Nature Communications.

In materials such as metals, electrons move freely, allowing them to conduct electricity. However, as interactions between electrons become stronger, freedom of motion can be suppressed. Under these conditions, materials undergo a phenomenon known as a Mott metal-insulator transition, where they change from a conducting metal into an insulating state in which electrons become effectively immobile.