  The notion of topological phases has been extended to higher-order and has
been generalized to different dimensions. As a paradigm, Cd3As2 is predicted to
be a higher-order topological semimetal, possessing three-dimensional (3D) bulk
Dirac fermions, two-dimensional (2D) Fermi arcs, and one-dimensional (1D) hinge
states. These topological states have different characteristic length scales in
electronic transport, allowing to distinguish their properties when changing
sample size. Here, we report an anomalous dimensional reduction of supercurrent
transport by increasing the size of Dirac semimetal Cd3As2-based Josephson
junctions. An evolution of the supercurrent quantum interferences from a
standard Fraunhofer pattern to a superconducting quantum interference device
(SQUID)-like one is observed when the junction channel length is increased. The
SQUID-like interference pattern indicates the supercurrent flowing through the
1D hinges. The identification of 1D hinge states should be valuable for deeper
understanding the higher-order topological phase in a 3D Dirac semimetal.
