Identification of strongly interacting organic semimetals

Abstract

Dirac- and Weyl point- and line-node semimetals are characterized by a zero band gap with simultaneously vanishing density of states. Given a sufficient interaction strength, such materials can undergo an interaction instability, e.g., into an excitonic insulator phase. Due to generically flat bands, organic crystals represent a promising materials class in this regard. We combine machine learning, density functional theory, and effective models to identify specific example materials. Without taking into account the effect of many-body interactions, we found the organic charge transfer salts (EDT-TTF-I${}_2$)${}_2$(DDQ)$\cdot ($CH${}_3$CN) and TSeF-TCNQ and a bis-1,2,3-dithiazolyl radical conductor to exhibit a semimetallic phase in our ab initio calculations. Adding the effect of strong particle-hole interactions for (EDT-TTF-I${}_2$)${}_2$(DDQ)$\cdot ($CH${}_3$CN) and TSeF-TCNQ opens an excitonic gap in the order of 60 meV and 100 meV, which is in good agreement with previous experiments on these materials.

arXiv comment11 pages, 9 figures

References in corpus (27)

• Dirac materials
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Dirac Fermions in Solids - from High Tc cuprates and Graphene to Topological Insulators and Weyl Semimetals
• Pressure-Induced Zero-Gap Semiconducting State in Organic Conductor $\alpha$-(BEDT-TTF)${}_2$I${}_3$ Salt
• Ghost excitonic insulator transition in layered graphite
• Filling constraints for spin-orbit coupled insulators in symmorphic and non-symmorphic crystals
• Filling-Enforced Gaplessness in Band Structures of the 230 Space Groups
• Observation of an anisotropic Dirac cone reshaping and ferrimagnetic spin polarization in an organic conductor
• Interacting Weyl fermions: Phases, phase transitions and global phase diagram
• Coulomb interaction at the metal-insulator critical point in graphene
• Interacting line-node semimetal: Proximity effect and spontaneous symmetry breaking
• Band gap prediction for large organic crystal structures with machine learning
• Classification of stable Dirac and Weyl semimetals with reflection and rotational symmetry
• Global Phase Diagram of a Dirty Weyl Liquid and Emergent Superuniversality
• Insulating nature of strongly correlated massless Dirac fermions in an organic crystal
• Pressure-dependent optical investigations of $\alpha$-(BEDT-TTF)${}_2$I${}_3$: tuning charge order and narrow gap towards a Dirac semimetal
• Qsymm: Algorithmic symmetry finding and symmetric Hamiltonian generation
• Instabilities of Weyl-loop semi-metals
• Phase diagram of the Quantum Electrodynamics of 2D and 3D Dirac semimetals
• Interacting Dirac liquid in three-dimensional semimetals
• Excitonic Gap Formation in Pumped Dirac Materials
• Data Mining for Three-Dimensional Organic Dirac Materials: Focus on Space Group 19
• GTPack: A Mathematica group theory package for application in solid-state physics and photonics
• Excitonic instability in optically-pumped three-dimensional Dirac materials
• Chemical-Strain Induced Tilted Dirac Nodes in (BEDT-TTF)${}_2$X${}_3$ (X = I, Cl, Br, F) Based Charge-Transfer Salts
• Odd-frequency Berezinskii superconductivity in Dirac semimetals
• First-principles study of the charge ordered phase in $\kappa$-D${}_3$(Cat-EDT-TTF/ST)${}_2$: Stability of $\pi$-electron deuterium coupled ordering in hydrogen-bonded molecular conductors

Cited by in corpus (4)

• Shifting computational boundaries for complex organic materials
• Machine learning phases of an Abelian gauge theory
• Spin-orbit interactions may relax the rigid conditions leading to flat bands
• A universal neural network for learning phases and criticalities