Tensile and compressive strain tuning of a Kondo lattice

We present electrical resistivity measurements on the prototypical heavy-fermion metal ${\mathrm{YbRh}}_{2}{\mathrm{Si}}_{2}$ (YRS) under $a$-axis tensile and compressive strain and focus on the evolution of the resistivity maximum near 136 K that arises from the interplay of the Kondo effect and the crystal electric field (CEF) splitting. While compressive strain reduces ${T}_{\mathrm{max}}$, similar as previously reported for hydrostatic pressure, ${T}_{\mathrm{max}}$ is enhanced up to 145 K for 0.13% tensile strain. Model calculations for the strain effect on CEF splitting in YRS reveal a negligible shift of the levels. Instead, the enhancement of the resistivity maximum indicates a 20% increase of the Kondo temperature. This opens the perspective to access the hidden zero-field quantum critical point in pure YRS.