Anisotropic thermally activated flux-flow behavior in the layered superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>2</mml:mn><mml:mi>M</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mi>WS</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Han Zhang, Yuqiang Fang, Teng Wang, Yixin Liu, J. J. Chu, Zhuojun Li, Da Jiang, Gang Mu, Zengfeng Di, Fuqiang Huang
Abstract
$2M\ensuremath{-}{\mathrm{WS}}_{2}$ is a newly discovered superconductor with a rather high critical transition temperature $({T}_{c}=8.8\phantom{\rule{4pt}{0ex}}\mathrm{K})$ and topological surface states. Recently Majorana bound states were observed in magnetic vortices of this material. Thus uncovering the flux dynamics of the magnetic vortices is essential to further promote the physical understanding and its practical application in topological quantum computation. Here we report an in-depth investigation on this issue by the temperature- and field-dependent electric transport measurements. The magnitudes of activation energy under both field orientations are rather low, revealing a weak pinning strength of the flux in the present system. Moreover, clear anisotropic thermally activated flux-flow behaviors are revealed. Under the in-plane field ($H\ensuremath{\parallel}bc$), the activation energy $U$ shows a $(1\ensuremath{-}T/{T}_{c}){H}^{\ensuremath{-}\ensuremath{\alpha}}$ dependence indicating the three-dimensional feature, while under the out-of-plane field $(H\ensuremath{\perp}bc)$, $U$ is proportional to $(1\ensuremath{-}T/{T}_{c})lnH$, which suggests a two-dimensional liquid state for the vortices.