Superconducting Single-Layer T-Graphene and Novel Synthesis Routes

【摘要】 Single-layer superconductors are ideal materials for fabricating superconducting nano devices.However,up to date,very few single-layer elemental superconductors have been predicted and especially no one has been successfully synthesized yet.Here,using crystal structure search techniques and ab initio calculations,we predict that a single-layer planar carbon sheet with 4-and 8-membered rings called T-graphene is a new intrinsic elemental superconductor with superconducting critical temperature（T_c）up to around 20.8 K.More importantly,we propose a synthesis route to obtain such a single-layer T-graphene,that is,a T-graphene potassium intercalation compound（C₄ K with P4/mmm symmetry）is firstly synthesized at high pressure（>11.5 GPa）and then quenched to ambient condition;and finally,the single-layer T-graphene can be either exfoliated using the electrochemical method from the bulk C4 K,or peeled off from bulk T-graphite C4,where C4 can be obtained from C4 K by evaporating the K atoms.Interestingly,we find that the calculated T_c of C4 K is about 30.4 K at 0 GPa,which sets a new record for layered carbon-based superconductors.The present findings add a new class of carbon-based superconductors.In particular,once the single-layer T-graphene is synthesized,it can pave the way for fabricating superconducting devices together with other 2 D materials using the layer-by-layer growth techniques.更多还原

【Abstract】 Single-layer superconductors are ideal materials for fabricating superconducting nano devices.However,up to date,very few single-layer elemental superconductors have been predicted and especially no one has been successfully synthesized yet.Here,using crystal structure search techniques and ab initio calculations,we predict that a single-layer planar carbon sheet with 4-and 8-membered rings called T-graphene is a new intrinsic elemental superconductor with superconducting critical temperature（T_c）up to around 20.8 K.More importantly,we propose a synthesis route to obtain such a single-layer T-graphene,that is,a T-graphene potassium intercalation compound（C₄ K with P4/mmm symmetry）is firstly synthesized at high pressure（>11.5 GPa）and then quenched to ambient condition;and finally,the single-layer T-graphene can be either exfoliated using the electrochemical method from the bulk C4 K,or peeled off from bulk T-graphite C4,where C4 can be obtained from C4 K by evaporating the K atoms.Interestingly,we find that the calculated T_c of C4 K is about 30.4 K at 0 GPa,which sets a new record for layered carbon-based superconductors.The present findings add a new class of carbon-based superconductors.In particular,once the single-layer T-graphene is synthesized,it can pave the way for fabricating superconducting devices together with other 2 D materials using the layer-by-layer growth techniques.更多还原