Evidence for a Strong Topological Insulator Phase in ZrTe_{5}.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Zirconium telluride (ZrTe5) exhibits complex electronic properties, leading to debate regarding its classification as a topological insulator or a 3D Dirac semimetal.
• Understanding the precise electronic phase of ZrTe5 is crucial for exploring its potential in next-generation electronic devices.

Purpose of the Study:

• To comprehensively investigate the electronic and structural properties of ZrTe5.
• To definitively determine the topological nature of bulk ZrTe5.
• To elucidate the surface and bulk electronic states contributing to its unique properties.

Main Methods:

• Angle-resolved photoelectron spectroscopy (ARPES) to probe electronic band structure.
• Ab initio calculations to model electronic properties based on structural data.
• X-ray diffraction (XRD) to determine precise crystal structure and interlayer distances.
• Scanning tunneling spectroscopy (STS) to confirm surface electronic characteristics.

Main Results:

• Experimental and theoretical evidence confirms ZrTe5 as a strong topological insulator (STI).
• ARPES identified distinct surface and bulk states at the valence band edge.
• Ab initio calculations accurately reproduced band dispersion for the STI phase, consistent with XRD measurements.
• STS measurements verified the metallic surface states, supporting the topological nature.

Conclusions:

• ZrTe5 is definitively classified as a strong topological insulator.
• The study reconciles conflicting previous assignments of its electronic phase.
• The findings provide a solid foundation for future research and applications of ZrTe5 in topological electronics.