Effects of Zeroline and Ferrimagnetic Fluctuation on Nuclear Magnetic Resonance for Dirac Electrons in Molecular Conductor alpha-(BEDT-TTF)2I3

Abstract

We re-examine the wave function of two-dimensional massless Dirac electron in alpha-(BEDT-TTF)2I3 consisting of four molecules A, A', B and C in a unit cell, using a tight-binding model. We find zerolines in the Brillouin zone, on which the component of the wave function becomes zero for B or C sites. The zerolines, which are bounded by two Dirac points at k0 and pass through the M- or Y-points, result in a fact that the density of states of the B site exhibits no the Van Hove singularity near the energy of the Dirac points. By taking account of the on-site Coulomb interaction within the random phase approximation, we examine the spin fluctuation in order to investigate properties of the nuclear magnetic resonance for temperatures T > 50K. In the region for 100 < T < 300K, it is shown that the Knight sift for B-site monotonously decreases with decreasing temperature, owing to lack of the Van Hove singularity, while it shows a maximum for the other sites (A, A' and C sites). In the region for 50 < T < 100K, it is shown that the Knight sift is convex downward and the Korringa ratio increases with decreasing temperature for B-site. Such a behavior originates from the ferrimagnetic spin fluctuation related to the zerolines. These results are consistent with those of the nuclear magnetic resonance experiments.

10 pages, 7 figures

References in corpus (5)

• Tilted anisotropic Dirac cones in quinoid-type graphene and alpha-(BEDT-TTF)_2I_3
• Effects of the Zero-Mode Landau Level on Inter-Layer Magnetoresistance in Multilayer Massless Dirac Fermion Systems
• Possible Verification of Tilted Anisotropic Dirac Cone in α-(BEDT-TTF)_2 I_3 Using Interlayer Magnetoresistance
• Electronic Properties Close to Dirac Cone in Two-Dimensional Organic Conductor $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• ${}^{13}$C NMR Study on the Charge-Disproportionated Conducting State in the Quasi-Two-Dimensional Organic Conductor $\alpha$-(BEDT-TTF)${}_2$I${}_3$

Cited by in corpus (11)

• Observation of an anisotropic Dirac cone reshaping and ferrimagnetic spin polarization in an organic conductor
• Anomalous Spin Correlations and Mass-Generating Excitonic Instability of Interacting Weyl Fermions
• Insulating nature of strongly correlated massless Dirac fermions in an organic crystal
• Correlation Effects on Charge Order and Zero-Gap State in the Organic Conductor α-(BEDT-TTF)2I3
• Transport properties of organic Dirac electron system α-(BEDT-TSeF)${}_2$I${}_3$
• Spin excitations in the quasi-two-dimensional charge-ordered insulator $\alpha$-(BEDT-TTF)${}_2$I${}_3$ probed via ${}^{13}$C NMR
• Interaction-induced quantum spin Hall insulator in the organic Dirac electron system $\alpha$-(BEDT-TSeF)${}_2$I${}_3$
• Analysis of Dirac Point in the Organic Conductor $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Inversion Symmetry and Wave-Function-Nodal-Lines of Dirac Electrons in Organic Conductor alpha-(BEDT-TTF)_2I_3
• Effect of Long-Range Coulomb Interaction on NMR Shift in Massless Dirac Electrons of Organic Conductor
• Fragment-orbital-dependent spin fluctuations in the single-component molecular conductor [Ni(dmdt)${}_2$]