Surface and electronic structure at atomic length scales of the nonsymmorphic antiferromagnet Eu5 In2 Sb6

We performed scanning tunneling microscopy and spectroscopy (STM/STS) measurements to investigate the Zintl phase Eu5In2Sb6, a nonsymmorphic antiferromagnet. The theoretical prediction of a nontrivial Fermi surface topology stabilized by the nonsymmorphic symmetry motivated our research. On the cleaved (010) plane, we obtained striped patterns that can be correlated to the stacking of the [In2Sb6]10-double chains along the crystallographic c axis. The attempted cleavage along the a axis revealed a more complex pattern. We combined the STS measurement on nonreconstructed (010) and (081) surfaces with DFT calculations to further elucidate the electronic structure of Eu5In2Sb6. From our investigations so far, direct experimental evidence of the predicted topological surface states remains elusive.