A capacitor may include a first thin-film electrode layer; a second thin-film electrode layer; and a dielectric layer between the first thin-film electrode layer and the second thin-film electrode layer. The first thin-film electrode layer and the second thin-film electrode layer may include a conductive perovskite-type crystal structure. The dielectric layer may include a metal oxide having a dielectric perovskite-type crystal structure. The dielectric layer may be an epitaxial layer. The metal oxide may include a first element in a cubooctahedral site, a second element in an octahedral site, and a third element in an octahedral site. A valency of the third element may be lower than a valency of the second element, and the third element may be a dopant.