Back to Search
Start Over
Renormalization of Coulomb interactions in a system of two-dimensional tilted Dirac fermions
- Source :
- Physical Review B. 97
- Publication Year :
- 2018
- Publisher :
- American Physical Society (APS), 2018.
-
Abstract
- We investigate the effects of long-ranged Coulomb interactions in a tilted Dirac semimetal in two dimensions by using the perturbative renormalization-group (RG) method. Depending on the magnitude of the tilting parameter, the undoped system can have either Fermi points (type I) or Fermi lines (type II). Previous studies usually performed the renormalization-group transformations by integrating out the modes with large momenta. This is problematic when the Fermi surface is open, like type-II Dirac fermions. In this work we study the effects of Coulomb interactions, following the spirit of Shankar [Rev. Mod. Phys. 66, 129 (1994)], by introducing a cutoff in the energy scale around the Fermi surface and integrating out the high-energy modes. For type-I Dirac fermions, our result is consistent with that of the previous work. On the other hand, we find that for type-II Dirac fermions, the magnitude of the tilting parameter increases monotonically with lowering energies. This implies the stability of type-II Dirac fermions in the presence of Coulomb interactions, in contrast with previous results. Furthermore, for type-II Dirac fermions, the velocities in different directions acquire different renormalization even if they have the same bare values. By taking into account the renormalization of the tilting parameter and the velocities due to the Coulomb interactions, we show that while the presence of a charged impurity leads only to charge redistribution around the impurity for type-I Dirac fermions, for type-II Dirac fermions, the impurity charge is completely screened, albeit with a very long screening length. The latter indicates that the temperature dependence of physical observables are essentially determined by the RG equations we derived. We illustrate this by calculating the temperature dependence of the compressibility and specific heat of the interacting tilted Dirac fermions.
- Subjects :
- Physics
High Energy Physics::Lattice
Observable
Fermi surface
02 engineering and technology
021001 nanoscience & nanotechnology
01 natural sciences
Semimetal
Renormalization
symbols.namesake
Dirac fermion
Quantum electrodynamics
Quantum mechanics
0103 physical sciences
Compressibility
symbols
Coulomb
010306 general physics
0210 nano-technology
Fermi Gamma-ray Space Telescope
Subjects
Details
- ISSN :
- 24699969 and 24699950
- Volume :
- 97
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi...........7a42501c45528fa605639bf37874e9e4