Hida family of theta lift from U(1) to definite U(2)

Let K/F be a CM extension satisfying the ordinary assumption for an odd prime p. In this article, we construct Hida families that interpolate theta lifts of algebraic Hecke characters to a definite unitary group U(2) defined from skew-Hermitian spaces over K, and show that the Hida family is primitive when the central L-value of the branch character of the family satisfies certain non-vanishing modulo p conditions.