High pressure studies in SrFe2As2, CaMn2Bi2 and CeAuBi2 compounds

Abstract

In many compounds, including the cuprates, the Fe-based and the heavy-fermion superconductors, the suppression of a magnetic order leads to unusual ground states such as unconventional superconductivity and non-Fermi-liquid states. These ground states can be tuned by chemical substitution, magnetic fields, uniaxial strain, and applied hydrostatic pressure. In particular, applied pressure is an ideal non-symmetric-breaking tuning parameter, as there is no introduction of disorder in the system. Therefore, the application of external pressure is a desirable route to suppress magnetic ordered states and induce novel ground states. This project proposes to explore this route by means of electrical resistivity and AC calorimetry experiments under high pressures (~10 GPa) and low temperatures (~300 mK) for SrFe2As2, CaMn2Bi2 and CeAuBi2. All compounds order antiferromagnetically at 204 K, 150 K and 12 K, respectively. The first is a Fe-based superconductor, in which high pressure experiments will shed new light on the relation of structural distortions and the appearance of superconductivity. The latter two are new materials in which the suppression of the antiferromagnetic order may lead to unusual ground states. It is worth mentioning that the experiments performed at the Los Alamos National Laboratory (LANL) will reach ranges of temperature and pressure which cannot be achieved at our group in Brazil. Also, LANL is one of the most renowned laboratories in the world, performing cutting-edge scientific research, and Prof. Dr. Joe D. Thompson is a world-renowned expert in experiments under high pressures, with an extensive list of high impact publications and numerous citations. Moreover, Dr. Priscila Rosa is also a great expert in experiments under high pressures and will help in my supervision. Therefore, this internship abroad will allow the advancement of the results acquired in my project to ranges that cannot be achieved at my research group. This internship also will provide the knowledge of several experimental techniques, such as AC calorimetry under pressure, which I intend to perform at my research group afterwards. Further, this project will strengthen the collaboration between UNICAMP and LANL, and provide a successful route for the exchange of students. In this regard, this internship will bring an extensive list of benefits to me and to my group in Brazil, which are of great value to the development of my academic life and science in Brazil. (AU)