Graphene has many advantageous properties,but its lack of an electronic band gap makes this two-dimensional material impractical for many nanoelectronic applications,for example,field-effect transistors.This problem c...Graphene has many advantageous properties,but its lack of an electronic band gap makes this two-dimensional material impractical for many nanoelectronic applications,for example,field-effect transistors.This problem can be circumvented by opening up a confinement-induced gap,through the patterning of graphene into ribbons having widths of a few nanometres.The electronic properties of such ribbons depend on both their size and the crystallographic orientation of the ribbon edges.Therefore,etching processes that are able to differentiate between the zigzag and armchair type edge terminations of graphene are highly sought after.In this contribution we show that such an anisotropic,dry etching reaction is possible and we use it to obtain graphene ribbons with zigzag edges.We demonstrate that the starting positions for the carbon removal reaction can be tailored at will with precision.展开更多
Topological materials host robust properties,unaffected by microscopic perturbations,owing to the global topological properties of the bulk electron system.Materials in which the topological invariant can be changed b...Topological materials host robust properties,unaffected by microscopic perturbations,owing to the global topological properties of the bulk electron system.Materials in which the topological invariant can be changed by easily tuning external parameters are especially sought after.Zirconium pentatelluride(ZrTe_(5))is one of a few experimentally available materials that reside close to the boundary of a topological phase transition,allowing the switching of its invariant by mechanical strain.Here,we unambiguously identify a topological insulator–metal transition as a function of strain,by a combination of ab initio calculations and direct measurements of the local charge density.Our model quantitatively describes the response to complex strain patterns found in bubbles of few layer ZrTe_(5) without fitting parameters,reproducing the mechanical deformation-dependent closing of the band gap observed using scanning tunneling microscopy.We calculate the topological phase diagram of ZrTe_(5) and identify the phase at equilibrium,enabling the design of device architectures,which exploit the topological switching characteristics of the system.展开更多
基金Financial support by hungarian scientific research fund-national office for research and technology(OTKA-NKTH)grants Nos.67793,67851,and 67842 is acknowledged.
文摘Graphene has many advantageous properties,but its lack of an electronic band gap makes this two-dimensional material impractical for many nanoelectronic applications,for example,field-effect transistors.This problem can be circumvented by opening up a confinement-induced gap,through the patterning of graphene into ribbons having widths of a few nanometres.The electronic properties of such ribbons depend on both their size and the crystallographic orientation of the ribbon edges.Therefore,etching processes that are able to differentiate between the zigzag and armchair type edge terminations of graphene are highly sought after.In this contribution we show that such an anisotropic,dry etching reaction is possible and we use it to obtain graphene ribbons with zigzag edges.We demonstrate that the starting positions for the carbon removal reaction can be tailored at will with precision.
基金The work was conducted within the framework of the Topology in Nanomaterials Lendulet project,Grant No.LP2017-9/2017with support from the European H2020 GrapheneCore3 Project No.881603+3 种基金Financial support fromÉlvonal Grant KKP 138144,NKFIH OTKA grant K132869 and TKP20121 NKPA grant is also acknowledgedP.V.and L.O.acknowledge the support of the Janos Bolyai Research Scholarship the Bolyai+Scholarship of the Hungarian Academy of SciencesL.O.acknowledges financial support from NKFIH OTKA grant FK124723 and K131938L.O.and J.K.acknowledges the support from the Ministry of Innovation and Technology for the Quantum Information National Laboratory.
文摘Topological materials host robust properties,unaffected by microscopic perturbations,owing to the global topological properties of the bulk electron system.Materials in which the topological invariant can be changed by easily tuning external parameters are especially sought after.Zirconium pentatelluride(ZrTe_(5))is one of a few experimentally available materials that reside close to the boundary of a topological phase transition,allowing the switching of its invariant by mechanical strain.Here,we unambiguously identify a topological insulator–metal transition as a function of strain,by a combination of ab initio calculations and direct measurements of the local charge density.Our model quantitatively describes the response to complex strain patterns found in bubbles of few layer ZrTe_(5) without fitting parameters,reproducing the mechanical deformation-dependent closing of the band gap observed using scanning tunneling microscopy.We calculate the topological phase diagram of ZrTe_(5) and identify the phase at equilibrium,enabling the design of device architectures,which exploit the topological switching characteristics of the system.
