Designing an artificial Lieb lattice on a metal surface

Qiu, Wen-Xuan; Li, Shuai; Gao, Jin-Hua; Zhou, Yi; Zhang, Fuchun

doi:10.1103/physrevb.94.241409

Cited by 49 publications

(49 citation statements)

References 40 publications

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“…The electrons in the flat band have nearly zero group velocity and their kinetic energy is almost quenched. Thus the Coulomb interaction plays a major role to form some many-body states, such as FM or AF state [39]. Furthermore, these flat bands results in a very large density of states (DOS).…”

Section: Band Structures Of Esdw Statesmentioning

confidence: 99%

Excited spin density waves in zigzag graphene nanoribbons

2018

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In addition to the well-known anti-ferromagnetic and ferromagnetic edge states in zigzag graphene nanoribbons (GNR), we find that there also exist some excited spin density wave (ESDW) states, the energies of which are close to the anti-ferromagnetic state (ground state). We thus argue that these ESDW states may coexist in experiment. Our numerical results from the self-consistent mean-field method as well as the first-principles calculations indicate that the allowed ESDWs are commensurate; and their dispersion curves are linear in the long wave limit. The coupling of the two edge portions in an ESDW becomes very weak in a wide GNR, in which case these ESDW portions may have different phases. Finally our calculations in the non-equilibrium Green's function theory combined with the Hubbard model show that these ESDW states can also exist in some localized (middle or terminal) region of GNR.

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Section: Band Structures Of Esdw Statesmentioning

confidence: 99%

Excited spin density waves in zigzag graphene nanoribbons

2018

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“…For example, Kekulé structure, graphene pn junctions, deformed graphene, graphene nanoribbons, point and line defects, topological domain wall states, Lieb lattice, quasicrystalline structure, and fractal electronics have been realized in molecular designers [23][24][25][26][27][28][29][30]. These systems exhibit exciting physics such as Gauge field, edge states and flat band [35][36][37][38], to name a few.…”

Section: Introductionmentioning

confidence: 99%

Symmetry breaking in molecular artificial graphene

et al. 2019

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Symmetry breaking in graphene has profound impacts on its physical properties. Here we emulate symmetry breaking in artificial graphene systems by assembling coronene molecules on a Cu(111) surface. We apply two strategies: (1) differentiating the on-site energy of two sublattices of a honeycomb lattice and (2) uniaxially compressing a honeycomb lattice. The first one breaks the inversion symmetry while the second one merges the Dirac cones. The scanning tunneling spectroscopy shows that in both cases the local density of states undergo characteristic changes. Muffin-tin simulations reveal that the observed changes are associated with a band gap opened at the Dirac point. Furthermore, we propose that using larger molecules or molecules strongly scattering the surface state electrons can induce an indirect gap. Experimental and theoretical methodsSingle-crystal Cu(111) substrate was cleaned by cycles of Ar + sputtering and subsequently annealing to 530°C. The sample was characterized using an ultra-high vacuum (10 −10 mbar base pressure) scanning tunneling microscope (STM) system (Omicron GmbH) at cryogenic temperature (5 K). Coronene molecules (Sigma Aldrich) were thermally deposited at 290°C on the Cu(111) substrate held at room temperature and then OPEN ACCESS RECEIVED

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“…Although the Lieb lattices have been realized in photonic crystals 8,9 and cold atom systems [10][11][12] , creating an electronic version has proved more challenging. Recently, Qiu et al showed that the artificial Lieb lattices can be realized on the metallic copper surface 13 . The artificial Lieb Lattice was rapidly confirmed in experiments 14,15 , providing a realistic electronic Lieb lattice system to explore the above-mentioned physics.…”

Section: Introductionmentioning

confidence: 99%

Disorder-induced topological phase transitions on Lieb lattices

Chen

Zhou

2017

Phys. Rev. B

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Motivated by the very recent experimental realization of electronic Lieb lattices and research interest on topological states of matter, we study the topological phase transitions driven by Andersontype disorder on spin-orbit coupled Lieb lattices in the presence of spin-independent and dependent staggered potentials. By combining the recursive Green's function and self-consistent Born approximation methods, we found that both time-reversal-invariant and time-reversal-symmetry-broken spin-orbit coupled Lieb lattice systems can host the disorder-induced gapful topological phases, including the quantum spin Hall insulator (QSHI) and quantum anomalous Hall insulator (QAHI) phases. For the time-reversal-invariant case, the disorder induces a topological phase transition directly from a normal insulator (NI) to the QSHI. While for the time-reversal-symmetry-broken case, the disorder can induce either a QAHI-QSHI phase transition or a NI-QAHI-QSHI phase transition, depending on the initial state of the system. Remarkably, the time-reversal-symmetry-broken QSHI phase can be induced by Anderson-type disorder on the spin-orbit coupled Lieb lattices without time-reversal symmetry.

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Designing an artificial Lieb lattice on a metal surface

Cited by 49 publications

References 40 publications

Excited spin density waves in zigzag graphene nanoribbons

Excited spin density waves in zigzag graphene nanoribbons

Symmetry breaking in molecular artificial graphene

Disorder-induced topological phase transitions on Lieb lattices

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