Effect of Long-Range Coulomb Interaction on NMR Shift in Massless Dirac Electrons of Organic Conductor

Abstract

The nuclear magnetic resonance (NMR) with the site-dependent shift, at low temperatures is examined for a massless Dirac electrons in the organic conductor, alpha-(BEDT-TTF)_2I_3, where the sites of the four molecules in the unit cell are given by A (= A'), B, and C. The Dirac cone exists within an energy of 0.01 eV between the conduction and valence bands. The magnetic response function is calculated by taking account of the long-range Coulomb interaction and electron doping. Calculating the interaction within the first order in the perturbation, the chemical potential is determined self-consistently, and the self-energy and vertex corrections are taken to satisfy the Ward identity. The site-dependent shift is calculated at low temperatures of 0.0002 < T < 0.002 (T is temperature in the unit of eV) by correctly treating the wave function of the Dirac cone. At lower (higher) temperatures the self-energy (vertex) correction of the shift at all sites except for B is dominant and the sign is negative (positive), while the sign of the correction at the B site is always negative. For moderate doping, the shift as a function of T takes a minimum. The relevance of the shift to the experiment is discussed.

21 pages, 17 figures

References in corpus (6)

• Observation of an anisotropic Dirac cone reshaping and ferrimagnetic spin polarization in an organic conductor
• Electronic Properties Close to Dirac Cone in Two-Dimensional Organic Conductor $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Inter-Band Effects of Magnetic Field on Hall Conductivity in Multi Layered Massless Dirac Fermion System $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Renormalization Effects on Quasi-Two-Dimensional Organic Conductor α-(BEDT-TTF)2I3
• Berry Curvature of the Dirac Particle in $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Effects of Zeroline and Ferrimagnetic Fluctuation on Nuclear Magnetic Resonance for Dirac Electrons in Molecular Conductor alpha-(BEDT-TTF)2I3