In the quest to develop high-temperature superconductors, RIKEN physicists have made a significant discovery that may pave the way for materials that can superconduct at room temperature. Their study, published in the journal Physical Review B, delves into the behavior of electrons in a material as it approaches superconductivity. By examining the relationship between nematicity and superconductivity, the researchers hope to gain a deeper understanding of the mechanisms behind these phenomena.
Superconductors, materials that can carry electrical current without any resistance, have immense potential for various applications such as powerful electromagnets and magnetic sensors. However, the drawback is that superconductivity typically occurs at low temperatures. Scientists are eager to discover high-temperature superconductors that can operate at more convenient temperatures, opening up a broader range of possibilities.
Conventional superconductors exhibit superconductivity when electrons pair up, preventing scattering as they flow through a material. As certain materials approach this superconducting state, they enter a “nematic phase” where electrons align into stripes. The connection between nematicity and superconductivity is still not fully understood, making it a topic of intense research.
To gain insights into the relationship between nematicity and superconductivity, the RIKEN researchers focused on iron selenide. This material only superconducts at an extremely low temperature of -265°C, just 8°C above absolute zero. However, it is possible to achieve superconductivity at higher temperatures through the application of pressure or by manipulating the material’s chemical composition.
Iron selenide undergoes a nematic phase transition at approximately -183°C. During this phase, the arrangement of atoms in the material’s crystal lattice changes, and certain electrons can adopt different energy states. Understanding the relative significance of these structural and electronic factors in driving nematicity has been a subject of debate among researchers.
The RIKEN team made a breakthrough by studying an ultrathin film of iron selenide on a lanthanum aluminate base. By suppressing the structural change during the transition to the nematic phase, they were able to observe all the electronic hallmarks of this phase, even though the lattice structure remained the same. This finding suggests that the nematic phase originates solely from changes in the energy states of specific electrons.
The thin-film material developed by the RIKEN physicists offers a valuable platform for studying the behavior of electrons in the nematic phase, devoid of any accompanying structural alterations. This novel approach can lead to a deeper understanding of the intricate relationship between nematicity and superconductivity, as well as shed light on the underlying mechanisms of superconductivity itself. By unraveling these mysteries, researchers can potentially develop strategies for creating high-temperature superconductors that operate at room temperature.
This groundbreaking study by RIKEN physicists paves the way for new insights into superconductivity and its connection to nematicity. By investigating the behavior of electrons in materials approaching superconductivity, scientists are one step closer to realizing high-temperature superconductors with a wide range of practical applications. With continued research and experimentation, the dream of materials that can superconduct at room temperature may soon become a reality.