title: Evidence of van Hove singularities in ordered grain boundaries of graphene.
abstract: It has long been under debate whether the electron transport performance of graphene could be enhanced by the possible occurrence of van Hove singularities in grain boundaries. Here, we provide direct experimental evidence to confirm the existence of van Hove singularity states close to the Fermi energy in certain ordered grain boundaries using scanning tunneling microscopy. The intrinsic atomic and electronic structures of two ordered grain boundaries, one with alternative pentagon and heptagon rings and the other with alternative pentagon pair and octagon rings, are determined. It is firmly verified that the carrier concentration and, thus, the conductance around ordered grain boundaries can be significantly enhanced by the van Hove singularity states. This finding strongly suggests that a graphene nanoribbon with a properly embedded ordered grain boundary can be a promising structure to improve the performance of graphene-based electronic devices.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Chuanxu
authors.initials: C
authors.lastname: Ma
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Sun
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Yeliang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Qunxiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Aidi
authors.initials: A
authors.lastname: Zhao
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Jinlong
authors.initials: J
authors.lastname: Yang
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: J G
authors.initials: JG
authors.lastname: Hou