Spin-charge separation and electron pairing instabilities in Hubbard nanoclusters

Journal Article · Wed Jul 01 04:00:00 EDT 2009 · Ultramicroscopy

DOI:https://doi.org/10.1016/j.ultramic.2009.03.032· OSTI ID:1040137

Kocharian, A; Davenport, J; Fernando, G W; Palandage, K

Electron charge and spin pairing instabilities in various cluster geometries for attractive and repulsive electrons are studied exactly under variation of interaction strength, electron doping and temperature. The exact diagonalization, level crossing degeneracies, spin-charge separation and separate condensation of paired electron charge and opposite spins yield intriguing insights into the origin of magnetism, ferroelectricity and superconductivity seen in inhomogeneous bulk nanomaterials and various phenomena in cold fermionic atoms in optical lattices. Phase diagrams resemble a number of inhomogeneous, coherent and incoherent nanoscale phases found recently in high-T{sub c} cuprates, manganites and multiferroic nanomaterials probed by scanning tunneling microscopy. Separate condensation of electron charge and spin degrees at various crossover temperatures offers a new route for superconductivity, different from the BCS scenario. The calculated phase diagrams resemble a number of inhomogeneous paired phases, superconductivity, ferromagnetism and ferroelectricity found in Nb and Co nanoparticles. The phase separation and electron pairing, monitored by electron doping and magnetic field surprisingly resemble incoherent electron pairing in the family of doped high-T{sub c} cuprates, ruthenocuprates, iron pnictides and spontaneous ferroelectricity in multiferroic materials.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1040137
• Report Number(s): BNL--90392-2009-JA; KC020401H
• Journal Information: Ultramicroscopy, Journal Name: Ultramicroscopy Journal Issue: 8 Vol. 109; ISSN 0304-3991; ISSN ULTRD6
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
97 MATHEMATICS AND COMPUTING
ATOMS
CUPRATES
ELECTRONS
FERMIONS
FERROMAGNETISM
IRON
MAGNETIC FIELDS
MAGNETISM
MICROSCOPY
PHASE DIAGRAMS
PNICTIDES
PROBES
SCANNING TUNNELING MICROSCOPY
SPIN
SUPERCONDUCTIVITY