Ferromagnetic properties in low-doped zigzag graphene nanoribbons

Li, Shuaiyu; Tian, Lin; Shi, Lingli; Wen, Lin; Ma, Tianxing

doi:10.1088/0953-8984/28/8/086001

Cited by 7 publications

(7 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[22][23][24][25][26][27][28] At graphene edges the density of states may be peaked due to the presence of edge-localized states close to the Fermi level. 29 Especially at extended zigzag edges this leads to a phenomenon called edge magnetism, for which various theories [30][31][32] predict ferromagnetic (FM) intraedge and antiferromagnetic (AFM) interedge correlations. The proposed magnetism is similar to the flat-band ferromagnetism appearing in the orbital-active optical honeycomb lattice, 33 where the band flatness dramatically amplifies the interaction effect, driving the ferromagnetic transition even with a relatively weak repulsive interaction.…”

Section: Introductionmentioning

confidence: 99%

Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons

Yang

Huang

et al. 2017

Sci Rep

Self Cite

View full text Add to dashboard Cite

We reveal an edge spin triplet p-wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons. By employing a method that combines random-phase approximation, the finite-temperature determinant quantum Monte Carlo approach, and the ground-state constrainedpath quantum Monte Carlo method, it is shown that such a spin-triplet pairing is mediated by the ferromagnetic fluctuations caused by the flat band at the edge. The spin susceptibility and effective pairing interactions at the edge strongly increase as the on-site Coulomb interaction increases, indicating the importance of electron-electron correlations. It is also found that the doping-dependent ground-state p-wave pairing correlation bears some similarity to the famous superconducting dome in the phase diagram of a high-temperature superconductor, while the spin correlation at the edge is weakened as the system is doped away from half filling.Triplet superconductivity (SC) has been a focus of modern condensed matter physics because of its possible connection to topological quantum information and computation [1][2][3][4][5][6][7][8][9][10] . It has been proposed that a gapless Majorana bound state would localize at the end of the one-dimensional spinless p-wave superconductor 1 , which could be used to practically realize topological quantum computation 11,12 . To realize such a Majorana bound state in real material, the superconducting proximity effect was proposed [13][14][15] , and experimental evidence of its existence was recently reported 16 . Here, we explore the possibility of intrinsic triplet SC, which is generated by an electronic correlation.In this paper, we reveal a possible edge-spin triplet p-wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons with appropriate interactions. Graphene, a single layer of carbon, has generated immense interest ever since its experimental discovery 17,18 . Recently, experimental advances in doping methods have made it possible to change the type of carriers (electrons or holes) 19,20 , opening the doors for exotic phases, such as SC and magnetism induced by repulsive interactions. For instance, it was shown by the two-stage renormalization-group calculation that unconventional SC is induced by weak repulsive interactions in honeycomb Hubbard models that are away from half-filling 21 , and that a topological d + id SC is induced in a heavily doped system [22][23][24][25][26][27][28] . At graphene edges the density of states may be peaked due to the presence of edge-localized states close to the Fermi level 29 . Especially at extended zigzag edges this leads to a phenomenon called edge magnetism, for which various theories 30-32 predict ferromagnetic (FM) intraedge and antiferromagnetic (AFM) interedge correlations. The proposed magnetism is similar to the flat-band ferromagnetism appearing in the orbital-active optical honeycomb lattice 33 , where the band flatness dramatically amplifies the interaction effect, driving the ferromagnetic transition even wit...

show abstract

Section: Introductionmentioning

confidence: 99%

Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons

Yang

Huang

et al. 2017

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…14,15 First-principles studies of graphene triangles (S = 0) and hexagons (S = 0) 4 further confirmed the applicability of Lieb's theorem concerning S in the half-filled one-orbital Hubbard model for bipartite lattices. 16 Upon charge doping, it was found in the same model that the spin polarizations on the two ribbon edges can change from antiparallel to parallel, forming the ferromagnetic correlated edge (FMCE)…”

mentioning

confidence: 81%

Width-Tuned Magnetic Order Oscillation on Zigzag Edges of Honeycomb Nanoribbons

Chen

Zhou

et al. 2017

Nano Lett.

View full text Add to dashboard Cite

Quantum confinement and interference often generate exotic properties in nanostructures. One recent highlight is the experimental indication of a magnetic phase transition in zigzag-edged graphene nanoribbons at the critical ribbon width of about 7 nm [G. Z. Magda et al., Nature 514, 608 (2014)]. Here we show theoretically that with further increase in the ribbon width, the magnetic correlation of the two edges can exhibit an intriguing oscillatory behavior between antiferromagnetic and ferromagnetic, driven by acquiring the positive coherence between the two edges to lower the free energy. The oscillation effect is readily tunable in applied magnetic fields. These 1 novel properties suggest new experimental manifestation of the edge magnetic orders in graphene nanoribbons, and enhance the hopes of graphene-like spintronic nanodevices functioning at room temperature.

show abstract

“…In fact, many of the recently discovered flat bands systems show an enhanced susceptibility towards superconductivity [27,31]. However, alternative orders have also been shown to be strongly enhanced, including flat band ferromagnetism [35,36] and robust magnetic order along the zigzag edge of graphene [37][38][39][40][41][42]. Thus, while ordering is very often expected in flat band systems, it is not generally known if the large DOS peak actually favors superconductivity or other orders.…”

Section: Introductionmentioning

confidence: 99%

Universal phase diagrams with superconducting domes for electronic flat bands

Löthman

Black‐Schaffer

2017

Phys. Rev. B

View full text Add to dashboard Cite

Condensed matter systems with flat bands close to the Fermi level generally exhibit, due to their very large density of states, extraordinary high critical ordering temperatures of symmetry breaking orders, such as superconductivity and magnetism. Here we show that the critical temperatures follow one of two universal curves with doping away from a flat band depending on the ordering channel, which completely dictates both the general order competition and the phase diagram. Notably, we find that orders in the particle-particle channel (superconducting orders) survive decisively further than orders in the particle-hole channel (magnetic or charge orders) because the channels have fundamentally different polarizabilities. Thus, even if a magnetic or charge order initially dominates, superconducting domes are still likely to exist on the flanks of flat bands. We apply these general results to both the topological surface flat bands of rhombohedral ABC-stacked graphite and to the van Hove singularity of graphene.c 1 2T − c . We are able to establish the general phase diagram exactly for any interactions in an ideally flat band system. Remarkably, we also show that the results remain valid arXiv:1611.04893v2 [cond-mat.supr-con]

show abstract

Ferromagnetic properties in low-doped zigzag graphene nanoribbons

Cited by 7 publications

References 41 publications

Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons

Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons

Width-Tuned Magnetic Order Oscillation on Zigzag Edges of Honeycomb Nanoribbons

Universal phase diagrams with superconducting domes for electronic flat bands

Contact Info

Product

Resources

About