Role of band filling in tuning the high-field phases of URu 2 Si 2
We present a detailed study of the low temperature and high magnetic eld phases in the chemical substitution series URu 2 Si 2-x Px using electrical transport and magnetization in pulsed magnetic elds up to 65T. Within the hidden order x-regime (0 < x ≲ 0.035) the eld induced ordering that was earlier seen for x = 0 is robust, even as the hidden order temperature is suppressed. Earlier work shows that for 0.035 ≲ x ≲ 0.26 there is a Kondo lattice with a no-ordered state that is replaced by antiferromagnetism for 0.26 ≲ x ≲ 0.5. We observe a simpli ed continuation of the eld induced order in the no-order x-regime and an enhancement of the field induced order upon the destruction of the antiferromagnetism with magnetic field. These results closely resemble what is seen for URu 2-x RhxSi 2 a, from which we infer that charge tuning dominantly controls the ground state of URu 2 Si 2 , regardless of whether s/p or d-electrons are replaced. Contraction of the unit cell volume may also play a role at large x. This provides guidance for determining the specific factors that lead to hidden order versus magnetism in this family of materials and constrains possible models for hidden order.