A memory device may be provided that includes: a substrate; a coupling layer which is located on the substrate and has electrical conductivity; a meta-atomic layer which is located on or under the coupling layer; a memory layer which is located on the meta-atomic layer; and an electrode layer which is located on the memory layer and has electrical conductivity. The memory layer is composed of a material which produces spontaneous polarization at a voltage equal to or higher than a predetermined voltage. Through this, the memory device can be electrically driven and can continuously maintain modulated optical characteristics. Also, the memory device according to the embodiment of the present invention can modulate optical characteristics by multiple electrical inputs.