Low temperature specific heat of Yb2Ti2O7 single crystals

We study the specific heat of Yb2Ti2O7 single crystals at low temperatures down to 0.4 K and in magnetic fields along the [110] crystalline direction. There is a small peak near 0.4 K at low magnetic fields, signaturing a first-order transition, and its field dependence is consistent with that for H || [100] but different from that for H || [111]. The experimental data also show a broad peak at about 2 K, which has a nonmonotonic change with increasing field. This road peak is originated from the spin correlations and its field dependence can be understood from the recent numerical linked-cluster calculations [Hayre et al., Phys. Rev. B 87, 184423 (2013)]