I apologize for any confusion caused. In the context of my previous response, VG refers to vanadium garnet, not vertical graphene. Vanadium garnet, also known as vanadium-doped yttrium iron garnet (YIG), is a material used in various applications such as magneto-optical devices and spintronics. If you have any specific questions or need further information regarding vertical graphene, please let me know, and I'll be glad to assist you.