Figure 1: Phase diagram of CeRhIn₅.

(a) Pressure-field phase diagram of CeRhIn₅ for fields applied along the c-direction. At the critical pressure P_c, a first-order phase transition suppressing the anti-ferromagnetism (AFM) occurs within the superconducting state. Under zero applied pressure at the critical magnetic field H_c, similarly a first-order phase transition into a density wave (DW) state is found, which is the main result of our study. The transition persists up to temperatures of 2 K, above which it becomes unobservable. The DW state clearly coexists with the AFM order, yet it remains an open question if it persists beyond the AFM phase boundary into the paramagnetic state. The (P, T) data is reproduced from ref. 35 and T_N(H) from ref. 20. (b) SEM micrograph of a FIB carved ~60 × 60-μm slice of CeRhIn₅ (purple). Scale bar, 50 μm. The (a,c)-plane-oriented slice was structured into a U-shaped geometry and contacted by FIB-assisted platinum deposition (blue). Through the lower-left contacts, a shared current is applied along the ‘U’, passing through two resistivity bars along the c-direction (red) and one along the a-direction (green). The c axis bars are both 31.6 μm long with a cross-section of 1.4 × 4 μm, and the a axis bar is 34.5 μm long with a cross-section of 2.2 × 4 μm. The high residual resistivity ratios (ρ_a(300 K)/ρ_a(80 mK)~258, ρ_c(300 K)/ρ_c(80 mK)~268), the good quantitative agreement with the temperature dependence of the resistivity on macroscopic crystals³⁶ and the observation of Shubnikov–de Haas oscillations in fields as low as 4 T evidences the high crystal quality of the FIB-prepared devices.