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Isoelectronic perturbations to f-d-electron hybridization and the enhancement of hidden order in URu₂Si₂.

ABSTRACT: Electrical resistivity measurements were performed on single crystals of URu_2-x Os _x Si₂ up to x = 0.28 under hydrostatic pressure up to P = 2 GPa. As the Os concentration, x, is increased, 1) the lattice expands, creating an effective negative chemical pressure P _ch(x); 2) the hidden-order (HO) phase is enhanced and the system is driven toward a large-moment antiferromagnetic (LMAFM) phase; and 3) less external pressure P _c is required to induce the HO→LMAFM phase transition. We compare the behavior of the T(x, P) phase boundary reported here for the URu_2-x Os _x Si₂ system with previous reports of enhanced HO in URu₂Si₂ upon tuning with P or similarly in URu_2-x Fe _x Si₂ upon tuning with positive P _ch(x). It is noteworthy that pressure, Fe substitution, and Os substitution are the only known perturbations that enhance the HO phase and induce the first-order transition to the LMAFM phase in URu₂Si₂ We present a scenario in which the application of pressure or the isoelectronic substitution of Fe and Os ions for Ru results in an increase in the hybridization of the U-5f-electron and transition metal d-electron states which leads to electronic instability in the paramagnetic phase and the concurrent formation of HO (and LMAFM) in URu₂Si₂ Calculations in the tight-binding approximation are included to determine the strength of hybridization between the U-5f-electron states and the d-electron states of Ru and its isoelectronic Fe and Os substituents in URu₂Si₂.

SUBMITTER: Wolowiec CT

PROVIDER: S-EPMC8157968 | biostudies-literature |

REPOSITORIES: biostudies-literature

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