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In an effort to elucidate the unknown hidden ordered state at T₀ ~ 17.5 K in the heavy fermion compound URu₂Si₂, temperature dependent electrical resistivity measurements were performed on the electron doping chemical substitution series Si → P under quasi-hydrostatic pressures up to 21 kbar. Previous studies show that electron doping causes the HO to be rapidly suppressed towards zero temperature over a small x-range, after which there is a broad paramagnetic (PM) region that is eventually replaced by antiferromagnetic (AFM1) order at large x^[1,2]. Our results indicate that, like x = 0, HO transforms to AFM2 at critical pressures that decrease with increasing x, while the PM and AFM1 states are robust against pressure. We will present the resulting T - x - P phase diagram and discuss the ordered states in the electronic phase space surrounding URu₂Si₂.
[1]Gallagher A. et al., Nat. Commun. 7 10712 (2016). [2]Gallagher A. et al., J. Phys.: Condens. Matter 29 024004 (2016).