We study the fixed point subalgebra of a certain class of lattice vertex
operator algebras by an automorphism of order 3, which is a lift of a
fixed-point-free isometry of the underlying lattice. We classify the
irreducible modules for the subalgebra. Moreover, the rationality and the
C2​-cofiniteness of the subalgebra are established. Our result contains the
case of the vertex operator algebra associated with the Leech lattice.Comment: 77 page