In the journal Nature, scientists report the discovery of a potentially new state of matter.
The results of the experiments show that in the case of superconductors in strong magnetic fields, the phenomenon of violation of electron symmetry is observed. Finding similarities and differences among classes of materials with such properties, scientists can establish key components that have new properties, such as superconductivity.
Superconductors with heavy fermions are compounds of rare earth metals and actinides.
In a heavy fermion superconductor CeRhIn5, a so-called electronic nematic state appears in a strong magnetic field, in which the electrons in the material are aligned in such a way as to reduce the symmetry in the primary crystal. Now this seems to be a universal property of non-traditional superconductors. Unconventional superconductivity arises at the phase boundary separating the magnetically ordered and disordered phases of the material.
"The appearance of electronic ordering, called non-mathematical behavior, in model heavy fermionic superconductors suggests the relationship between nematicity and unconventional superconductivity. Hence it follows that nematicity is habitual for superconducting materials, "states physicist Philip Ronning from the Los Alamos National Laboratory, the lead author of the study. Heavy fermions are intermetallic compounds that include rare earth elements and actinides.
"Heavy fermion materials have a different hierarchy of energy scales than transition metals or organic substances, but they have the same physical properties with respect to back, charge and degree of freedom in the grid," he adds.
The researchers observed the appearance of a fluctuating nematic state at the quantum critical point CeRhIn5, which occurs when the magnetic field is 50 Tesla. Nematic states characterize liquid crystals in which the molecules are aligned in parallel, but not periodically. Nematic-like states were previously observed in transient metallic systems at the point of magnetic and superconducting phase transitions. The appearance of this property indicates a relationship between nematicity and unconventional superconductivity. However, the new nematic state found in CeRhIn5, compared to other systems, is that it can easily rotate in the direction of the magnetic field strength.
The experiment was carried out on a powerful pulsed magnetic field generator at the National High Magnetic Field Laboratory in Los Alamos, because powerful magnetic fields were needed to achieve its results. In addition, for the experiment, special micron devices, made with the help of ion beam milling, which was performed by German specialists, were needed. This made it possible to carry out transport measurements in strong magnetic fields.
Superconductivity is widely used in magnetic resonance imaging (MRI), particle accelerators, in devices for magnetic confinement of plasma and radio frequency and microwave filters.
