Title: Discovery of magnetic phase transitions in heavy-fermion superconductor CeRh2As2

Authors: G. Chajewski, D. Kaczorowski

Journal: Physical Review Letters

DOI: 10.1103/PhysRevLett.132.076504

Chajewski 2

The article published recently in Physical Review Letters describes the continuation of research on heavy-fermion superconductor CeRh2As2. It presents the results of detailed specific heat measurements carried out on previously obtained single crystals (see also Horizontal flux growth as an efficient preparation method of CeRh2As2 single crystals).

High-quality samples and the use of a dedicated experimental approach enabled the detection of a magnetic first-order phase transition within the superconducting state of the compound. This hitherto unobserved feature, along with other noticed similarities to antiferromagnetic heavy-fermion superconductors CeRhIn5 and Ce2RhIn8, sparked a radical change in the point of view on the physical properties of CeRh2As2. This discovery led to proposing an alternative straightforward interpretation of the experimental data, which does not align with the description suggested in the literature so far. Contrary to the previous scenario, ascribing the appearance of T0-anomaly in the specific heat data to the presence of a unique quadrupole density wave, in the new description, it has been assumed that this anomaly is a manifestation of long-range magnetic ordering (presumably similar to those occurring in CeRhIn5 and Ce2RhIn8). In turn, the first-order transition has been assigned to the reconstruction of the magnetic structure of CeRh2As2. Such a description allows one to avoid significant difficulties in explaining some other experimental results for this material.

Furthermore, in the article, there has been proposed an innovative measurement approach enabling the study of the evolution of first-order phase transitions in a magnetic field not only in CeRh2As2 but also in other compounds.