Band Structure Driven Thermoelectric Response of Topological Semiconductor ZrTe${}_5$

Abstract

We report a transport, thermodynamic, and spectroscopic study of the recently identified topological semiconductor ZrTe${}_5$ with a focus on elucidating the connections between its band structure and unusual thermoelectric properties. Using time and angle resolved photoemission spectroscopy (tr-ARPES) we observe a small electronic band gap and temperature dependent Fermi level which traverses from a single valence to conduction band with lowering temperature, consistent with previous reports. This low temperature Fermi surface closely matches that derived from quantum oscillations, suggesting it is reflective of the bulk electronic structure. The Seebeck and low field Nernst response is characterized by an unusually large and non-monotonic temperature evolution. We find this can be quantitatively explained using a semiclassical model based on the observed band character and a linear temperature shifting of the Fermi level. Additionally, we observe a large, non-saturating enhancement of both thermoelectric coefficients in magnetic field. We show this can be captured by the Zeeman energy associated with a large effective $g$-factor of 25.8 consistent with that derived from Lifshitz-Kosevich analysis of the quantum oscillations. Together these observations provide a comprehensive picture of ZrTe${}_5$ as a model high mobility semiconductor and potential platform for significant magnetic field driven thermoelectricity.

10 pages, 4 figures

References in corpus (6)

• Topological Insulators with Inversion Symmetry
• Evidence for a Strong Topological Insulator Phase in $\mathrm{ZrT}{\mathrm{e}}_5$
• Spectroscopic evidence for bulk-band inversion and three-dimensional massive Dirac fermions in ZrTe5
• Large Nernst effect and field enhanced transversal ZT in ZrTe5
• Thermodynamically Induced Transport Anomaly in Dilute Metals ZrTe${}_5$ and HfTe${}_5$
• Robust and tunable Weyl phases by coherent infrared phonons in ZrTe${}_5$

Cited by in corpus (6)

• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Revealing temperature evolution of the Dirac band in ZrTe${}_5$ via magneto-infrared spectroscopy
• Engineering a pure Dirac regime in ZrTe${}_5$
• Quasi-Dirac points in electron-energy spectra of crystals
• Effect of pressure on the transport properties and thermoelectric performance of Dirac semimetal ZrTe5
• First-principles studies of fermiology in topological phases of bulk ZrTe${}_5$