Coexistence of Ferroelectriclike Polarization and Dirac-like Surface State in TaNiTe5

By combining angle-resolved photoemission spectroscopy, scanning tunneling microscopy, atomic force microscope based piezoresponse force microscopy and first-principles calculations, we have studied the low-energy band structure, atomic structure, and charge polarization on the surface of a topological semimetal candidate TaNiTe5. Dirac-like surface states were observed on the (010) surface by angleresolved photoemission spectroscopy, consistent with the first-principles calculations. On the other hand, piezoresponse force microscopy reveals a switchable ferroelectriclike polarization on the same surface. We propose that the noncentrosymmetric surface relaxation observed by scanning tunneling microscopy could be the origin of the observed ferroelectriclike state in this novel material. Our findings provide a new platform with the coexistence of a ferroelectriclike surface charge distribution and novel surface states.

Automated summary

By combining various experimental and computational techniques, the low-energy band structure, atomic structure, and charge polarization on the surface of a topological semimetal candidate TaNiTe5 have been studied. Dirac-like surface states and switchable ferroelectric-like polarization were observed, and the noncentrosymmetric surface relaxation was proposed as the origin of the observed ferroelectric-like state in this novel material.