Scientists discover new state of matter

A group of scientists discovered a potential new state of matter that may help explain phenomena like superconductivity.

The study was published recently in the journal Nature.

Key highlights

• Researchers from the Los Alamos National Laboratory in the U.S. showed that among superconducting materials in high magnetic fields, the phenomenon of electronic symmetry breaking is common.

• The ability to find similarities and differences among classes of materials with phenomena such as this helps establish the essential ingredients that cause novel functionalities such as superconductivity.

• The high-magnetic-field state of the heavy fermion superconductor CeRhIn5 revealed a state in which the material’s electrons aligned in such a way to apparently reduce the symmetry of the original crystal. It is something that appears to be universal among unconventional superconductors.

• Unconventional superconductivity develops near a phase boundary separating magnetically ordered and magnetically disordered phases of a material.

• The appearance of the electronic alignment, called nematic behavior, in a prototypical heavy-fermion superconductor underlines the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be common among correlated superconducting materials.

• Using transport measurements near the field-tuned quantum critical point of CeRhIn5 at 50 Tesla, the researchers observed a fluctuating nematic-like state. A nematic state is most well known in liquid crystals, wherein the molecules of the liquid are parallel but not arranged in a periodic array.

• Nematic-like states have been observed in transition metal systems near magnetic and superconducting phase transitions. The occurrence of this property points to nematicity's correlation with unconventional superconductivity. However, the difference of the new nematic state found in CeRhIn5 relative to other systems is that it can be easily rotated by the magnetic field direction.

What is superconductivity?

• Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials, called superconductors, when cooled below a characteristic critical temperature.

• It was discovered by Dutch physicist Heike Kamerlingh Onnes on 8 April 1911, in Leiden, the Netherlands.

• Superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.

• The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics.