Single crystal growth of (Hf, Sc, RE)V2Ga4 (RE = rare earth) and (Fe, Co, Ru)1-xRMxGa3 (RM = refractory metals) compounds and the study of their Fermi surface, electronic structure, and superconducting properties under extreme conditions

Abstract

During the regular doctoral project in Brazil, several interesting results were found from the point of view of superconductivity for compounds that crystallize in the prototype structures YbMo2Al4 and IrIn3. For the first case, the compound HfV2Ga4 presents superconductivity with a critical temperature equal to 4.1K and several signatures of multiband behaviors, mainly in the upper and lower critical field diagrams and in the electronic component of the specific heat, in addition, calculations of first principles point for the existence of two bands cutting the Fermi level for this material. Finally, the same calculations suggest that ScV2Ga4 is a possible multiband superconducting material with a critical temperature higher than that observed in the compound with Hf, which in fact has already been observed experimentally, the compound ScV2Ga4 becomes superconducting with Tc = 8.0K approximately. On the other hand, the FeGa3 and CoGa3 compounds which are respectively semiconductor and a diamagnetic metal, become superconductors when the Fe or Co atoms are replaced by Mo atoms with critical temperatures of 8.1K and 6.8K respectively and have a strong linear dependence on the critical critical field diagram as a function of temperature. Finally, the objective of this BEPE project is to synthesize these compounds in monocrystalline form and characterize the superconducting properties under extreme conditions, with magnetic fields greater than 9.0 T, temperatures lower than 2.0K and pressures up to 2.5 GPa, these conditions would make possible observation of quantum oscillations to characterize the Fermi surface of these materials, as well as nuclear magnetic resonance measurements, with the same objective. (AU)