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Published on: April 9, 2018
The metal-insulator transition in dimerized Hückel chains
Antonio Monari1, Gian Luigi Bendazzoli, Stefano Evangelisti
1Dipartimento di Chimica Fisica e Inorganica, Universita di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy. amonari@ms.fci.unibo.it
The Journal of Chemical Physics
|December 3, 2008
Summary
Investigating metal-insulator transitions in linear chains reveals that dimerization drives this change. Removing specific eigenvectors corrects spurious metallic behavior in open chains, restoring insulating properties.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Theoretical Chemistry
Background:
- The metal-insulator transition is a fundamental phenomenon in materials science.
- Linear chains with Hückel Hamiltonians provide a simplified model for studying electronic properties.
- Dimerization of bond lengths and hopping integrals significantly impacts chain behavior.
Purpose of the Study:
- To investigate the metal-insulator transition in linear chains.
- To analyze the role of dimerization in inducing this transition.
- To identify and correct spurious metallic behavior in specific chain configurations.
Main Methods:
- Utilizing a one-electron Hückel Hamiltonian to model linear chains.
- Analyzing three key indicators: the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, polarizability, and localization tensor.
- Investigating the impact of alternating hopping integrals and eigenvectors in open chains.
Main Results:
- Dimerization of chain bond lengths induces dimerization of hopping integrals, driving the metal-insulator transition.
- Even open chains with weakly bonded end atoms exhibit spurious metallic behavior due to quasidegenerated eigenvalues.
- Removing specific eigenvectors from the Hamiltonian rectifies this spurious metallic behavior, revealing the inherent insulating nature.
Conclusions:
- The study clarifies the mechanism of metal-insulator transitions in dimerized linear chains.
- It highlights the critical influence of chain-end bonding on electronic properties.
- A method is presented to accurately determine the insulating behavior of alternating chains by addressing spurious eigenvalues.
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