Graphene, the classic one-atom-thick two-dimensional (2D) material with hexagonal lattice of sp 2 -bonded carbon atoms (a carbon atom bound to three atoms is sp 2 hybridized. When carbon is bonded to four other atoms, the hybridization is sp 3 ), was first theoretically discovered by Wallace [1] in 1947 and then was experimentally realized around 1970s. [2,3] Another form of carbon atoms, known as onedimensional (1D) carbon nanotube (CNT), was uncovered later in 1991 [4] and reported to be made out of a single graphene layer later in 1993. [5,6] Since being discovered, these carbon-based materials have attracted intensive research interest due to their outstanding thermo-electromechanical properties. [7][8][9][10][11] For instance, the monolayer graphene exhibits a unique combination of ultrahigh mechanical properties (Young's modulus of %1 TPa and tensile strength of %130 GPa [10] ), high thermal conductivity (3000-5000 W m À1 K À1 for suspended monolayer graphene), [8,12] and high electrical conductivity (10 4 to 10 5 S m À1 ). [13,14] The unique properties of graphene and CNT make them exciting candidates in flexible electronic devices, [15,16] nanosensors, [17] complementary metal-oxidesemiconductor, [11] and nanoelectromechanical systems (NEMS). [18] Nevertheless, some of CNT's and graphene's intrinsic properties, such as the limited stretchability (%0.2) [19,20] and low dimensional (1D and 2D) features, [21] can hamper their applications.By introducing rationally designed underlying architectures as the constitutive unit cell, architected materials, so-called metamaterials, with unparalleled multiphysical properties can be developed at multiple scales, from nano to macro. [22][23][24][25][26][27][28][29] For example, 3D nanoarchitected pyrolytic carbon exhibits extreme energy dissipation, which is %70% superior to that of Kevlar composites and nanoscale polystyrene films, owing to its material architecture and nanoscale material size effects. [23] Recent advances in additive manufacturing (AM) have emerged as a frontrunner for the fabrication of architected metamaterials to construct arbitrary complex architectures in a wide range of length scales. For instance, the feature resolutions of the architectures can be below 100 nm by utilizing photolithography. [30] Hence, to fully leverage these new manufacturing techniques, it is essential to design and computationally optimize materials architectures at different length scales, especially nano-and atomic scales, to achieve desired properties. Two main strategies to date have been utilized to construct nanoarchitected metamaterials based on graphene sheets and CNTs by computational simulations.
