Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations

We have studied the electronic structure of Cu(tmdt)2, a material related to single-component molecular conductors, by first-principles calculations. The total energy calculations for several different magnetic configurations show that there is strong antiferromagnetic (AFM) exchange coupling along...

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Main Authors: Kiyoyuki Terakura, Shoji Ishibashi
Format: Article
Language:English
Published: MDPI AG 2012-08-01
Series:Crystals
Subjects:
Online Access:http://www.mdpi.com/2073-4352/2/3/1210
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author Kiyoyuki Terakura
Shoji Ishibashi
author_facet Kiyoyuki Terakura
Shoji Ishibashi
author_sort Kiyoyuki Terakura
collection DOAJ
description We have studied the electronic structure of Cu(tmdt)2, a material related to single-component molecular conductors, by first-principles calculations. The total energy calculations for several different magnetic configurations show that there is strong antiferromagnetic (AFM) exchange coupling along the crystal a-axis. The electronic structures are analyzed in terms of the molecular orbitals near the Fermi level of isolated Cu(tmdt)2 molecule. This analysis reveals that the system is characterized by the half-filled pdσ(−) band whose intermolecular hopping integrals have strong one-dimensionality along the crystal a-axis. As the exchange splitting of the band is larger than the band width, the basic mechanism of the AFM exchange coupling is the superexchange. It will also be shown that two more ligand orbitals which are fairly insensitive to magnetism are located near the Fermi level. Because of the presence of these orbitals, the present calculation predicts that Cu(tmdt)2 is metallic even in its AFM state, being inconsistent with the available experiment. Some comments will be made on the difference between Cu(tmdt)2 and Cu(dmdt)2.
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spelling doaj.art-136239769da24e568f494150e7a35ad02022-12-22T04:24:11ZengMDPI AGCrystals2073-43522012-08-01231210122110.3390/cryst2031210Electronic Structure of Cu(tmdt)2 Studied with First-Principles CalculationsKiyoyuki TerakuraShoji IshibashiWe have studied the electronic structure of Cu(tmdt)2, a material related to single-component molecular conductors, by first-principles calculations. The total energy calculations for several different magnetic configurations show that there is strong antiferromagnetic (AFM) exchange coupling along the crystal a-axis. The electronic structures are analyzed in terms of the molecular orbitals near the Fermi level of isolated Cu(tmdt)2 molecule. This analysis reveals that the system is characterized by the half-filled pdσ(−) band whose intermolecular hopping integrals have strong one-dimensionality along the crystal a-axis. As the exchange splitting of the band is larger than the band width, the basic mechanism of the AFM exchange coupling is the superexchange. It will also be shown that two more ligand orbitals which are fairly insensitive to magnetism are located near the Fermi level. Because of the presence of these orbitals, the present calculation predicts that Cu(tmdt)2 is metallic even in its AFM state, being inconsistent with the available experiment. Some comments will be made on the difference between Cu(tmdt)2 and Cu(dmdt)2.http://www.mdpi.com/2073-4352/2/3/1210single-component molecular conductorCu(tmdt)2electronic structurefirst-principles calculationantiferromagnetic state
spellingShingle Kiyoyuki Terakura
Shoji Ishibashi
Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations
Crystals
single-component molecular conductor
Cu(tmdt)2
electronic structure
first-principles calculation
antiferromagnetic state
title Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations
title_full Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations
title_fullStr Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations
title_full_unstemmed Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations
title_short Electronic Structure of Cu(tmdt)2 Studied with First-Principles Calculations
title_sort electronic structure of cu tmdt 2 studied with first principles calculations
topic single-component molecular conductor
Cu(tmdt)2
electronic structure
first-principles calculation
antiferromagnetic state
url http://www.mdpi.com/2073-4352/2/3/1210
work_keys_str_mv AT kiyoyukiterakura electronicstructureofcutmdt2studiedwithfirstprinciplescalculations
AT shojiishibashi electronicstructureofcutmdt2studiedwithfirstprinciplescalculations