Quantum Phase Transition in Organic Massless Dirac Fermion System $\alpha$-(BEDT-TTF)${}_2$I${}_3$ under pressure

Abstract

We investigate the effect of strong electronic correlation on the massless Dirac fermion system, $\alpha$-(BEDT-TTF)${}_2$I${}_3$, under pressure. In this organic salt, one can control the electronic correlation by changing pressure and access the quantum critical point between the massless Dirac fermion phase and the charge ordering phase. We theoretically study the electronic structure of this system by applying the slave-rotor theory and find that the Fermi velocity decreases without creating a mass gap upon approaching the quantum critical point from the massless Dirac fermion phase. We show that the pressure-dependence of the Fermi velocity is in good quantitative agreement with the results of the experiment where the Fermi velocity is determined by the analysis of the Shubnikov-de Haas oscillations in the doped samples. Our result implies that the massless Dirac fermion system exhibits a quantum phase transition without creating a mass gap even in the presence of strong electronic correlations.

arXiv comment5 pages, 4 figures

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Cited by in corpus (9)

• Pressure-induced phase switching of the Shubnikov de Haas oscillations in molecular Dirac fermion system $\alpha -$(BETS)${}_2$I${}_3$
• Experimental Confirmation of Massive Dirac Fermions in Weak Charge-Ordering State in α-(BEDT-TTF)_2I_3
• Evidence for three-dimensional Dirac semimetal state in strongly correlated organic quasi-two-dimensional material
• Narrow Zero Mode in Organic Massless Dirac Electron System $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Observations of $\nu =1$ Quantum Hall Effect and Inter-Band Effects of Magnetic fields on Hall Conductivity in Organic Massless Dirac Fermion System $\alpha$-(BETS)${}_2$I${}_3$ under Pressure
• Time-Reversal Symmetry-Breaking Flux State in an Organic Dirac Fermion System
• Robust orbital diamagnetism of correlated Dirac fermions in chiral Ising universality class
• Intervalley Tunneling and Crossover from the Positive to Negative Interlayer Magnetoresistance in Quasi-Two-Dimensional Dirac Fermion System with or without Mass Gap
• Anomalous Phase-Coherence Scaling in a Quantum-Critical Dirac Semimetal