Gap opening with ordering in Pr Fe4 P12 studied by local tunneling spectroscopy

We present measurements of the local tunneling density of states in the low temperature ordered state of Pr Fe4 P12. The temperature dependencies of the Fermi level density of states and of the integrated density of states at low bias voltages show anomalies at T 6.5 K, the onset of multipolar ordering as detected by specific heat and other macroscopic measurements. In the ordered phase, we find a local density of states with a V-shape form, indicating a partial gap opening over the Fermi surface. The size of the gap according to the tunneling spectra is about 2 meV.