Coulomb Interactions and Ferromagnetism in Pure and Doped Graphene

By N. M. R. Peres, Francisco Guinea, A. C. Castro Neto. 2005

161 citations recorded by the source corpus.

We study the presence of ferromagnetism in the phase diagram of the two-dimensional honeycomb lattice close to half-filling (graphene) as a function of the strength of the Coulomb interaction and doping. We show that exchange interactions between Dirac fermions can stabilize a ferromagnetic phase at low doping when the coupling is sufficiently large. In clean systems the zero-temperature phase diagram shows both first-order and second-order transition lines and two distinct ferromagnetic phases: one phase with only one type of carriers (either electrons or holes) and another with two types of carriers (electrons and holes). Using the coherent potential approximation we argue that disorder further stabilizes the ferromagnetic phase. This work should estimulate Monte Carlo calculations in graphene dealing with the long-range nature of the Coulomb potencial.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/d21bbd08ba7127c245a684af7057c6c3a68c0723

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In Atomic and Molecular Physics, and Optics

1. N. M. R. Peres
2. K. Novoselov
3. Francisco Guinea
4. E. Rossi
5. E. Hwang
6. S. Adam
7. A.K. Geim
8. A. C. Castro Neto

In Materials Chemistry

1. N. M. R. Peres
2. K. Novoselov
3. Francisco Guinea
4. E. Hwang
5. E. Rossi
6. S. Adam
7. A. C. Castro Neto
8. A.K. Geim

Citations in the corpus

• Observation of electron–hole puddles in graphene using a scanning single-electron transistor (2007, background): “from the Coulomb interaction K ex c E E E μ = + + [17-22].”
• Electronic transport in two-dimensional graphene (2010, methodology): “Assuming that the ground state does not have long-range order (Peres et al., 2005; Dahal et al., 2006; Min, Borghi et al., 2008), a practical and accurate approach to calculate the ground state of many-body problems is the density functional theory (DFT) (Hohenberg and Kohn, 1964; Kohn and Sham, 196”
• Graphene Quantum Dots: Graphene-Enhanced Nanomaterials for Wall Painting Protection (Adv. Funct. Mater. 44/2018) (2018, unknown): “Many methods have been introduced for its synthesis, the mostly reported methods are mechanical exfoliation (Novoselov et al., 2004), chemical vapour deposition (CVD), liquid phase exfoliation of graphite (Li et al., 2008), thermal sputtering of SiC and oxidation of graphite (Peres et al., 2005).”
• The electronic properties of graphene (2007, background): “This result indi ates that strongly orrelated ele -troni phases, su h as ferromagnetism (Peres et al., 2005)and Wigner rystals (Dahal et al., 2006) are suppressedin lean graphene.”
• Novel effects of strains in graphene and other two dimensional materials (2015, background): “Furthermore, uniaxial strain can also affect the onset of the ferromagnetic instability of neutral unstrained graphene under the long range Coulomb interaction [285], driving the instability to smaller couplings within the range of those expected for suspended graphene [322].”