title: Simultaneous and coordinated rotational switching of all molecular rotors in a network.
abstract: A range of artificial molecular systems has been created that can exhibit controlled linear and rotational motion. In the further development of such systems, a key step is the addition of communication between molecules in a network. Here, we show that a two-dimensional array of dipolar molecular rotors can undergo simultaneous rotational switching when applying an electric field from the tip of a scanning tunnelling microscope. Several hundred rotors made from porphyrin-based double-decker complexes can be simultaneously rotated when in a hexagonal rotor network on a Cu(111) surface by applying biases above 1 V at 80 K. The phenomenon is observed only in a hexagonal rotor network due to the degeneracy of the ground-state dipole rotational energy barrier of the system. Defects are essential to increase electric torque on the rotor network and to stabilize the switched rotor domains. At low biases and low initial rotator angles, slight reorientations of individual rotors can occur, resulting in the rotator arms pointing in different directions. Analysis reveals that the rotator arm directions are not random, but are coordinated to minimize energy via crosstalk among the rotors through dipolar interactions.
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: H
authors.initials: H
authors.lastname: Kersell
authors.affiliation: CEMES, CNRS, 29 rue J. Marvig, 31055 Toulouse, France.
authors.forename: R
authors.initials: R
authors.lastname: Stefak
authors.affiliation: CEMES, CNRS, 29 rue J. Marvig, 31055 Toulouse, France.
authors.forename: J
authors.initials: J
authors.lastname: Echeverria
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: V
authors.initials: V
authors.lastname: Iancu
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: U G E
authors.initials: UG
authors.lastname: Perera
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: A
authors.initials: A
authors.lastname: Deshpande
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.
authors.forename: K-F
authors.initials: KF
authors.lastname: Braun
authors.affiliation: CEMES, CNRS, 29 rue J. Marvig, 31055 Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Joachim
authors.affiliation: CEMES, CNRS, 29 rue J. Marvig, 31055 Toulouse, France.|Universite' de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse, France.
authors.forename: G
authors.initials: G
authors.lastname: Rapenne
authors.affiliation: Physics and Astronomy Department, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701, USA.|Center for Nanoscale Materials, Nanoscience and Technology Division, Argonne National Laboratory, Illinois 60439, USA.
authors.forename: S-W
authors.initials: SW
authors.lastname: Hla