De Haas-Van Alphen Measurements On The Antiferromagnet Urhin5

We report on the results of a de Haas-van Alphen (dHvA) measurement performed on the recently discovered antiferromagnet URhIn5 (T-N = 98 K), a 5 f analog of the well studied heavy fermion antiferromagnet CeRhIn5. We observe two small Fermi surfaces: a roughly spherical pocket beta, with F-beta similar or equal to 0.3 kT, and a pillow-shaped closed surface, alpha, with F-alpha similar or equal to 1.1 kT. In addition, we observe two higher frequencies (gamma 1) with F-gamma 1 similar or equal to 3.2 kT and gamma(2) with F-gamma 2 similar or equal to 3.5 kT that are seen only near the c axis, and that may arise on cylindrical Fermi surfaces. The measured cyclotron masses range from 1.9m(e) to 4.3m(e). A simple LDA+SO calculation performed for the paramagnetic ground state shows a very different Fermi surface topology, demonstrating a need for more advanced electronic structure calculations.