Scanning tunneling microscopy of the organic conductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)-cyclophane)][TCNQ]4

Shulong Li, Henry S. White, Michael Ward

Research output: Contribution to journalArticle

Abstract

Scanning tunneling microscopy (STM) studies of the (001) and (010) faces, of the molecular semiconductor [(η-C5Me5)2Ru(η66-[22](1,4)cyclophane)]2+[TCNQ] 4 2- (1, TCNQ = tetracyanoquinodimethane) are reported. The lattice constants determined from the density of states corrugation of the STM images are a = 13.8 ± 0.3 Å, b = 15.9 ± 0.2 Å, c = 16.6 ± 2 Å, β = 88° ± 2°, γ = 82° ± 2°, in good agreement with the X-ray crystal structure. STM images of both faces reveal local density of states (LDOS) associated with stacking of TCNQ molecules along the [100] direction in two crystallographically unique stacks. The tunneling current contrast conforms to the tetrameric periodicity of the TCNQ stacks observed in the crystal structure. Columnar regions of negligible tunneling current on the ac face are attributed to stacks of (η-C5Me5)2Ru(η66-[22](1,4)cyclophane)2+ dications. Each TCNQ column exhibits a tunneling current corrugation repeating at intervals of a that is attributed to tunneling into the conduction band of antiferromagnetic 2kF charge density wave (CDW) structure. The CDWs also exhibit corrugation, and antiphase modulation, at a/2 with respect to adjacent stacks. This is consistent with appreciable interstack Coulomb interactions and contributions from the magnetic 4kF structure, which based on the tight-binding approximation is equivalent to the canonical description (TCNQ)2 -(TCNQ)2 -. The STM data are in agreement with magnetic susceptibility and EPR studies, which indicate significant contribution of the 4kF state to the electronic structure of 1. The STM therefore provides characterization of the local electronic structure that is manifested in the bulk electronic properties of 1.

Original languageEnglish (US)
Pages (from-to)1082-1091
Number of pages10
JournalChemistry of Materials
Volume4
Issue number5
StatePublished - 1992

Fingerprint

Organic conductors
Scanning tunneling microscopy
Electronic structure
Crystal structure
Charge density waves
Magnetic structure
Coulomb interactions
Conduction bands
Magnetic susceptibility
Electronic properties
Lattice constants
Paramagnetic resonance
Modulation
tetracyanoquinodimethane
Semiconductor materials
X rays
Molecules

ASJC Scopus subject areas

  • Materials Chemistry
  • Materials Science(all)

Cite this

Scanning tunneling microscopy of the organic conductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)-cyclophane)][TCNQ]4 . / Li, Shulong; White, Henry S.; Ward, Michael.

In: Chemistry of Materials, Vol. 4, No. 5, 1992, p. 1082-1091.

Research output: Contribution to journalArticle

@article{5bec6436e97a4d1091813d4e6ae40f91,
title = "Scanning tunneling microscopy of the organic conductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)-cyclophane)][TCNQ]4",
abstract = "Scanning tunneling microscopy (STM) studies of the (001) and (010) faces, of the molecular semiconductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)cyclophane)]2+[TCNQ] 4 2- (1, TCNQ = tetracyanoquinodimethane) are reported. The lattice constants determined from the density of states corrugation of the STM images are a = 13.8 ± 0.3 {\AA}, b = 15.9 ± 0.2 {\AA}, c = 16.6 ± 2 {\AA}, β = 88° ± 2°, γ = 82° ± 2°, in good agreement with the X-ray crystal structure. STM images of both faces reveal local density of states (LDOS) associated with stacking of TCNQ molecules along the [100] direction in two crystallographically unique stacks. The tunneling current contrast conforms to the tetrameric periodicity of the TCNQ stacks observed in the crystal structure. Columnar regions of negligible tunneling current on the ac face are attributed to stacks of (η-C5Me5)2Ru(η6,η 6-[22](1,4)cyclophane)2+ dications. Each TCNQ column exhibits a tunneling current corrugation repeating at intervals of a that is attributed to tunneling into the conduction band of antiferromagnetic 2kF charge density wave (CDW) structure. The CDWs also exhibit corrugation, and antiphase modulation, at a/2 with respect to adjacent stacks. This is consistent with appreciable interstack Coulomb interactions and contributions from the magnetic 4kF structure, which based on the tight-binding approximation is equivalent to the canonical description (TCNQ)2 -(TCNQ)2 -. The STM data are in agreement with magnetic susceptibility and EPR studies, which indicate significant contribution of the 4kF state to the electronic structure of 1. The STM therefore provides characterization of the local electronic structure that is manifested in the bulk electronic properties of 1.",
author = "Shulong Li and White, {Henry S.} and Michael Ward",
year = "1992",
language = "English (US)",
volume = "4",
pages = "1082--1091",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "5",

}

TY - JOUR

T1 - Scanning tunneling microscopy of the organic conductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)-cyclophane)][TCNQ]4

AU - Li, Shulong

AU - White, Henry S.

AU - Ward, Michael

PY - 1992

Y1 - 1992

N2 - Scanning tunneling microscopy (STM) studies of the (001) and (010) faces, of the molecular semiconductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)cyclophane)]2+[TCNQ] 4 2- (1, TCNQ = tetracyanoquinodimethane) are reported. The lattice constants determined from the density of states corrugation of the STM images are a = 13.8 ± 0.3 Å, b = 15.9 ± 0.2 Å, c = 16.6 ± 2 Å, β = 88° ± 2°, γ = 82° ± 2°, in good agreement with the X-ray crystal structure. STM images of both faces reveal local density of states (LDOS) associated with stacking of TCNQ molecules along the [100] direction in two crystallographically unique stacks. The tunneling current contrast conforms to the tetrameric periodicity of the TCNQ stacks observed in the crystal structure. Columnar regions of negligible tunneling current on the ac face are attributed to stacks of (η-C5Me5)2Ru(η6,η 6-[22](1,4)cyclophane)2+ dications. Each TCNQ column exhibits a tunneling current corrugation repeating at intervals of a that is attributed to tunneling into the conduction band of antiferromagnetic 2kF charge density wave (CDW) structure. The CDWs also exhibit corrugation, and antiphase modulation, at a/2 with respect to adjacent stacks. This is consistent with appreciable interstack Coulomb interactions and contributions from the magnetic 4kF structure, which based on the tight-binding approximation is equivalent to the canonical description (TCNQ)2 -(TCNQ)2 -. The STM data are in agreement with magnetic susceptibility and EPR studies, which indicate significant contribution of the 4kF state to the electronic structure of 1. The STM therefore provides characterization of the local electronic structure that is manifested in the bulk electronic properties of 1.

AB - Scanning tunneling microscopy (STM) studies of the (001) and (010) faces, of the molecular semiconductor [(η-C5Me5)2Ru(η6,η 6-[22](1,4)cyclophane)]2+[TCNQ] 4 2- (1, TCNQ = tetracyanoquinodimethane) are reported. The lattice constants determined from the density of states corrugation of the STM images are a = 13.8 ± 0.3 Å, b = 15.9 ± 0.2 Å, c = 16.6 ± 2 Å, β = 88° ± 2°, γ = 82° ± 2°, in good agreement with the X-ray crystal structure. STM images of both faces reveal local density of states (LDOS) associated with stacking of TCNQ molecules along the [100] direction in two crystallographically unique stacks. The tunneling current contrast conforms to the tetrameric periodicity of the TCNQ stacks observed in the crystal structure. Columnar regions of negligible tunneling current on the ac face are attributed to stacks of (η-C5Me5)2Ru(η6,η 6-[22](1,4)cyclophane)2+ dications. Each TCNQ column exhibits a tunneling current corrugation repeating at intervals of a that is attributed to tunneling into the conduction band of antiferromagnetic 2kF charge density wave (CDW) structure. The CDWs also exhibit corrugation, and antiphase modulation, at a/2 with respect to adjacent stacks. This is consistent with appreciable interstack Coulomb interactions and contributions from the magnetic 4kF structure, which based on the tight-binding approximation is equivalent to the canonical description (TCNQ)2 -(TCNQ)2 -. The STM data are in agreement with magnetic susceptibility and EPR studies, which indicate significant contribution of the 4kF state to the electronic structure of 1. The STM therefore provides characterization of the local electronic structure that is manifested in the bulk electronic properties of 1.

UR - http://www.scopus.com/inward/record.url?scp=0011625124&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0011625124&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0011625124

VL - 4

SP - 1082

EP - 1091

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 5

ER -