Interplay between tilt, disorder, and Coulomb interaction in type-I Dirac fermions

Abstract

We investigate the mutual influence of tilt, disorder, and Coulomb interaction in a type-I Dirac semimetal (DSM) with x-direction tilt by performing a renormalization group analysis. The interplay between disorder and ordinary tilt generates an effective tilt along the x-direction, which is the physically observable one. There exist two types of disorder which increase the effective tilt and drive a phase transition from the DSM phase to the diffusive metal phase. The diffusive phase transition stops the increase of the effective tilt and the surface of the original Dirac cone in the diffusive metal phase is just slightly tilted. Surprisingly, the Dirac point is replaced by a bulk nodal arc in the diffusive metal phase. The Coulomb interaction suppresses the diffusive phase transition and therefore is harmful to the formation of bulk nodal arc. In contrast, there also exists other two types of disorder which reduce the effective tilt and induce no phase transition. For these two types of disorder, the Coulomb interaction enhances their low-energy relevances. Coexistence of Coulomb interaction with any of them leads to a stable infrared fixed point where the coupling strengths for two kinds of interaction are identical and the effective tilt vanishes. The original tilted Dirac semimetal now reacts like an untilted and interaction-free Dirac semimetal. Our results show that interplay between tilt, disorder, and Coulomb interaction results in rich low-energy properties for the tilted Dirac fermions. *

Emergent chiral symmetry in a three-dimensional interacting Dirac liquid

“…In this paper we only take the Hubbardlike short-range (momentumindependent) interactions into account. On the other hand, the long-range tail of the Coulomb interaction in Dirac materials only provide logarithmic correction to the Fermi velocity [26][27][28][29][30][31][32][33][34][35][36], without causing any transition to ordered states [29,31,33]. When simultaneously present with the short-range interactions, it can only cause non-universal shifts of the phase boundaries [32,34], without altering the underlying quantum critical behavior [31,33].…”

Emergent chiral symmetry in a three-dimensional interacting Dirac liquid

“…In this paper we only take the Hubbardlike short-range (momentum-independent) interactions into account. On the other hand, the long-range tail of the Coulomb interaction in Dirac materials only provide logarithmic correction to the Fermi velocity [26][27][28][29][30][31][32][33][34][35][36], without causing any transition to ordered states [29,31,33]. When simultaneously present with the short-range interactions, it can only cause non-universal shifts of the phase boundaries [32,34], without altering the underlying quantum critical behavior [31,33].…”

Theoretical Model for a Novel Electronic State in a Dirac Electron System Close to Merging: An Imaginary Element between Sulphur and Selenium

“…The calculations of the electronic structures and related quantities in the solid states require well-defined atomic parameters for all the atoms involved. Although DES materials with the disorder are seldom reported and have garnered considerable attention [27][28][29], the lack of the abovementioned calculation results has seriously hindered further studies on this CT complex and a clear understanding of the general DESs. All the electrical, magnetic, and optical properties of the DESs are governed by the intermolecular interactions between the STF molecules in α-STF 2 I 3 .…”

“…The calculations of the electronic structures and related quantities in the solid states require well-defined atomic parameters for all the atoms involved. Although DES materials with the disorder are seldom reported and have garnered considerable attention [27][28][29], the lack of the abovementioned calculation results has seriously hindered further studies on this CT complex and a clear understanding of the general DESs. We have recently proposed a tight-binding band structure of α-STF2I3 based on the overlapping integrals SSTF, assuming statistically averaged structures between all the possible molecular arrangements at each site in the disordered crystal (Figure 3; see Appendix for details) in addition to the assumption of tSTF/eV = −10SSTF, where tSTF We have recently proposed a tight-binding band structure of α-STF 2 I 3 based on the overlapping integrals S STF , assuming statistically averaged structures between all the possible molecular arrangements at each site in the disordered crystal (Figure 3; see Appendix A for details) in addition to the assumption of t STF /eV = −10S STF , where t STF represents the corresponding transfer integrals [21].…”