Abstract :
In this work, we give a new realization of Demazure crystals Bw(λ) of type An for any Weyl group element w and for certain dominant integral weights λ. The vectors of Bw(λ) are given by certain Young walls lying inside the extremal vector and which contain the highest weight vector, as diagrams. From this result, we also obtain descriptions for Demazure crystals in terms of semistandard tableaux.