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QMCHTC

Project QMCHTC
Research Area Materials Science
Principal Investigator(s) Sandro Sorella
Institution(s)
  • University of California Davis, USA
  • Universidad del Paí­s Vasco, Vitoria, Spain
  • Ecole Polytechnique, France
  • SISSA/ISAS, Trieste, Italy

Abstract

In this project we study two important high temperature (HTc) superconducting materials, La2CuO4 that is the prototype of copper oxide superconductors discovered in 1988, and LaFeAsO, representative of the novel iron based rare-earth oxypnictide superconductors.
By means of state-of-the-art quantum Monte Carlo (QMC) techniques, our main target is to understand whether the peculiar magnetic properties of the two materials are related to the pairing mechanism that leads to superconductivity. The superconducting regime in the iron-based and copper-oxide families occurs in close proximity to a long-range ordered antiferromagnetic state. This suggests a strong interplay between magnetism and HTc superconductivity, which is probably one of the most challenging problems in condensed matter physics.
In the past, different lattice models, such as the Hubbard and the t-J Hamiltonians, have been introduced for a simplified theoretical description of the HTc superconductors. Within these models a superconducting phase arising only from electron correlation has been found by several QMC techniques.
The purpose of this project is to apply for the first time these methods to an ab-initio study of the full electronic structure of La2CuO4 and LaFeAsO in order to get not only a qualitative but also a quantitative agreement with the experiments.
The project will be divided in three stages: in the first part we will perform careful and systematic tests on simple molecules based on Cu, O, Fe and As, and trigger important computational details, such as the quality of different pseudopotentials and the basis sets. In the second stage of the project we plan to study the CuO and FeAs planes. Finally, the full solid structures and their magnetic and superconducting properties will be investigated.
This project will be done in collaboration with different research groups and will require large computing facilities.

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