Universal scaling behavior under pressure in the heavy-fermion antiferromagnet CeRh 2 Si 2 : Si 29 NMR study

The microscopic origin of a magnetic phase diagram under pressure in the heavy-fermion antiferromagnet ${\mathrm{CeRh}}_{2}{\mathrm{Si}}_{2}$ was investigated using the $^{29}\mathrm{Si}$ nuclear magnetic resonance (NMR) technique. Owing to the characteristics of the hyperfine form factor at the Si site, which filters specific $\mathbit{q}$-dependent fluctuations around antiferromagnetic $\mathbit{q}$ vectors, we investigated the temperature and pressure dependences of $\mathbit{q}$-independent local fluctuations caused by the single-site Kondo effect. A universal scaling behavior observed on the energy scale of the local fluctuations in the entire pressure region demonstrates that the characteristic energy scale ${T}_{0}$ of Kondo interactions monotonically increases by applying pressure without a critical anomaly around the quantum critical pressure ${P}_{\mathrm{c}}$ of antiferromagnetism. Our NMR result agrees with the Doniach picture of the heavy-fermion phase diagram, where the progressive delocalization of the $f$ electrons occurs across ${P}_{\mathrm{c}}$, accompanied by the development of antiferromagnetic correlations among the $f$ electrons.