Wang Yongjian, Bömerich Thomas, Park Jinhong, Legg Henry F, Taskin A A, Rosch Achim, Ando Yoichi
Physics Institute II, University of Cologne, Zülpicher Straße 77, 50937 Köln, Germany.
Institute for Theoretical Physics, University of Cologne, Zülpicher Straße 77, 50937 Köln, Germany.
Phys Rev Lett. 2023 Oct 6;131(14):146602. doi: 10.1103/PhysRevLett.131.146602.
The Dirac material ZrTe_{5} at very low carrier density was recently found to be a nodal-line semimetal, where ultraflat bands are expected to emerge in magnetic fields parallel to the nodal-line plane. Here, we report that in very low carrier-density samples of ZrTe_{5}, when the current and the magnetic field are both along the crystallographic a axis, the current-voltage characteristics presents a pronounced nonlinearity which tends to saturate in the ultra quantum limit. The magnetic-field dependence of the nonlinear coefficient is well explained by the Boltzmann theory for flat-band transport, and we argue that this nonlinear transport is likely due to the combined effect of flat bands and charge puddles; the latter appear due to very low carrier densities.
最近发现，在极低载流子密度下的狄拉克材料ZrTe₅是一种节线半金属，在与节线平面平行的磁场中预计会出现超平带。在此，我们报告，在极低载流子密度的ZrTe₅样品中，当电流和磁场都沿晶体学a轴时，电流-电压特性呈现出明显的非线性，在超量子极限下趋于饱和。非线性系数的磁场依赖性可以通过平带输运的玻尔兹曼理论得到很好的解释，我们认为这种非线性输运可能是由于平带和电荷 puddles 的综合作用；后者是由于极低的载流子密度而出现的。
