Tuning the Decay Length of Long-Range Photocurrent in Weyl Semimetals by Engineering the Weighting Field.
basic_science · Level V
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- Record sourced from PubMed, PMID 41294382.
- Also identified by DOI 10.1021/acs.nanolett.5c05323.
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Abstract
In conventional materials, symmetry breaking induced by spatial inhomogeneities typically confines self-powered photocurrents to edges, corners, or interfaces. In this work, we observe long-range photocurrents with multidomain patterns extending from the contacts into the interior of homogeneous Weyl semimetals (WTe<sub>2</sub> and TaIrTe<sub>4</sub>) at room temperature. It is revealed that the long-range photocurrent is approximately proportional to the anisotropic divergence of the weighting field ((<b>σS</b>∇)·<b>E</b>). By increasing the conductivity anisotropy or enlarging the angle between the material's <i>a-</i>axis and the channel direction, the gradient of (<b>σS</b>∇)·<b>E</b> along the <i>a</i>-axis is reduced, and the decay length of the long-range photocurrent (<i>L</i><sub>d</sub>) is substantially increased. As a result, a large <i>L</i><sub>d</sub> of up to 20.5 μm is achieved in a TaIrTe<sub>4</sub> device with the <i>a</i>-axis oriented perpendicular to the channel direction, far exceeding typical photocurrent decay lengths observed in conventional low-dimensional materials.