We give a realization of the level zero fundamental weight representation $W(\varpi_k)$ of the quantum affine algebra $U_q'(\mf{ g})$, when $\mf{ g}$ has a maximal parabolic subalgebra of type $C_n$. We define a semisimple $U'_q({ \mf g})$-module structure on $\E^{ \otimes 2}$ in terms of q-deformed Clifford generators, where $\E$ is the exterior algebra generated by a dual natural representation $V$ of $U_q(\mf{ sl}_{ n})$. We show that each $W(\varpi_k)$ appears as an irreducible summand (not necessarily multiplicity free) in $\E^{ \otimes 2}$. As a byproduct, we obtain a simple description of the affine crystal structure of $W(\varpi_k)$ in terms of $n\times 2$ binary matrices and their $(\mf{ sl}_n,\mf{ sl}_2)$-bicrystal structure.
Categories: math.QA