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

TL;DR

This study reveals the coexistence of ferroelectric-like polarization and Dirac-like surface states in TaNiTe5, combining experimental techniques and calculations to explore its unique topological and polar properties.

Contribution

It demonstrates the simultaneous presence of ferroelectric-like polarization and topological surface states in TaNiTe5, a novel finding for this class of materials.

Findings

Dirac-like surface states observed on (010) surface

Switchable ferroelectric-like polarization detected

Surface reconstruction may cause ferroelectric-like state

Abstract

By combining angle-resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy (STM), piezoresponse force microscopy (PFM) 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 ARPES, consistent with the first-principles calculations. On the other hand, PFM reveals a switchable ferroelectric-like polarization on the same surface. We propose that the noncentrosymmetric surface reconstruction observed by STM could be the origin of the observed ferroelectric-like state in this novel material. Our findings provide a new platform with the coexistence of ferroelectric-like surface charge distribution and novel surface states.