Giant Nernst effect and field-enhanced transversal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>z</mml:mi><mml:mi>N</mml:mi></mml:msub><mml:mi mathvariant="normal">T</mml:mi></mml:math> in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">ZrTe</mml:mi><mml:mn>5</mml:mn></mml:msub></mml:math>
Peipei Wang, Chang-Woo Cho, Fangdong Tang, Peng Wang, Wenjie Zhang, Mingquan He, Genda Gu, Xiaosong Wu, Yonghong Shao, Liyuan Zhang
Abstract
Thermoelectric materials can recover electrical energy from waste heat and vice versa, which are of great significance in green energy harvesting and solid state refrigerators. The thermoelectric figure of merit ($z\mathrm{T}$) quantifies the energy conversion efficiency, and a large Seebeck or Nernst effect is crucial for the development of thermoelectric devices. Here we present a significantly large Nernst thermopower in topological semimetal ${\mathrm{ZrTe}}_{5}$, which is attributed to both strong Berry curvature and bipolar transport. The largest in-plane ${S}_{xy}$ (when B//b) approaches 1900 $\ensuremath{\mu}\mathrm{V}/\mathrm{K}$ at $T=100$ K and B = 13 T, and the out-of-plane ${S}_{xz}$ (when B//c) reaches 5000 $\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{V}/\mathrm{K}$. As a critical part of ${z}_{N}\mathrm{T}$, the linearly increased in-plane ${S}_{xy}$ and resistivity ${\ensuremath{\rho}}_{\mathrm{yy}}$ in regard to B induces an almost linear increasing transversal ${z}_{N}\mathrm{T}$ without saturation under high fields. The maximum ${z}_{N}\mathrm{T}$ of 0.12 was obtained at B = 13 T and $T=120$ K, which significantly surmounts its longitudinal counterpart under the same condition.