Evidence of decoupling of surface and bulk states in Dirac semimetal Cd3As2.

Dirac semimetals have attracted a great deal of current interests due to their potential applications in topological quantum computing, low-energy electronic devices, and single photon detection in the microwave frequency range. Herein are results from analyzing the low magnetic (B) field weak-antilocalization behaviors in a Dirac semimetal Cd3As2thin flake device. At high temperatures, the phase coherence lengthlϕfirst increases with decreasing temperature (T) and follows a power law dependence oflϕ∝T-0.4. Below âˆ¼3 K,lϕtends to saturate to a value of âˆ¼180 nm. Another fitting parameterα, which is associated with independent transport channels, displays a logarithmic temperature dependence forT > 3 K, but also tends to saturate below âˆ¼3 K. The saturation value, âˆ¼1.45, is very close to 1.5, indicating three independent electron transport channels, which we interpret as due to decoupling of both the top and bottom surfaces as well as the bulk. This result, to our knowledge, provides first evidence that the surfaces and bulk states can become decoupled in electronic transport in Dirac semimetal Cd3As2.