▎ 摘　　要

A hybrid structure that presents phases of three extended allotropes of carbon, nanotube, graphene, and diamond, is proposed in this work. According to our first-principles calculations, such structure can be made energetically stable through the application of pressures of the order of 100 kbar to alternate graphene nanotube layers, which were recently synthesized in large-area films. The existence of sp(3) dangling bonds in the hybrid structure gives rise to an exceptionally large density of states near the Fermi level, leading to a ferromagnetic ground state.