  A single material achieving multiple topological phases can provide potential
application for topological spintronics, whereas the candidate materials are
very limited. Here, we report the structure, physical properties, and possible
emergence of multiple topological phases in the newly discovered, air-stable
EuCuBi single crystal. EuCuBi crystallizes in a hexagonal space group P63/mmc
(No. 194) in ZrBeSi-type structure with an antiferromagnetic (AFM) ground state
below TN = 11.2 K. There is a competition between AFM and ferromagnetic (FM)
interactions below TN revealed by electrical resistivity and magnetic
susceptibility measurements. With the increasing magnetic field, EuCuBi evolves
from the AFM ground state with a small amount of FM component, going through
two possible metamagnetic phases, finally reaches the field-induced FM phase.
Based on the first-principles calculations, we demonstrate that the Dirac,
Weyl, and possible mirror Chern insulator can be achieved in EuCuBi by tuning
the temperature and applying magnetic field, making EuCuBi a promising
candidate for exploring multiple topological phases.
