Its unique properties raise many interesting questions.” A strange superconductor “With its order-of-magnitude higher transition temperature of 2.2 K, this material will not need a dilution refrigerator to be superconducting. “This new oxide interface makes the application of 2D superconducting devices more feasible,” Liu said. To obtain the superconducting interface, Liu, graduate student Xi Yan and coworkers grew thin layers of either europium oxide (EuO) or LAO on KTO using state-of-the-art thin film growth facilities at Argonne. In the new research, the team discovered that in KTO, interfacial superconductivity could emerge at much higher temperatures. Even with such low transition temperatures ( T C), the LAO/ STO interface has been heavily studied in the context of superconductivity, spintronics and magnetism.
However, to achieve such a superconducting state, the sample had to be cooled down to about 0.2 K - a temperature that is close to absolute zero (– 273.15 ☌), requiring a specialized apparatus known as a dilution refrigerator. Importantly, the superconductivity could be switched on and off using electric fields, just like in a transistor. It was later shown that that this material, called a 2D electron gas ( 2DEG) can even become superconducting - allowing the transport of electricity without dissipating energy. In 2004, scientists observed a thin sheet of conducting electrons between two other oxide insulators, LaAlO 3 ( LAO) and SrTiO 3 ( STO). Their results were published online in the journal Science on February 12. In the study, Argonne postdoctoral researcher Changjiang Liu and colleagues, working in a team led by Argonne materials scientist Anand Bhattacharya, have discovered that a novel 2D superconductor forms at the interface of an oxide insulator called KTaO 3 ( KTO). This interfacial superconductor has novel properties that raise new fundamental questions and might be useful for quantum information processing or quantum sensing. Department of Energy’s Argonne National Laboratory have discovered a new way to generate 2D superconductivity at a material interface at a relatively high - though still cold - transition temperature. All superconducting materials at regular pressures become superconducting at temperatures far below the coldest day outside. One of the foundational questions with superconducting materials involves the transition temperature - the extremely cold temperature at which a material becomes superconducting.
The vast majority of superconducting materials and devices are 3D, giving them properties that are well understood by scientists. Like semiconductors, superconducting materials have many important implications for technology, from magnets for MRIs to speeding up electrical connections or perhaps making possible quantum technology. More broadly, the interface between any two materials can have unique properties that are dramatically different from those found within either material separately, setting the stage for new discoveries. For example, transistors found in all our electronic devices work by controlling the electrons at interfaces of semiconductors. Interfaces in solids form the basis for much of modern technology.