Dirac cone pairs in silicene induced by interface Si-Ag hybridization: A first-principles effective band study

Lian, Chao; Meng, Sheng

doi:10.1103/physrevb.95.245409

Cited by 21 publications

(15 citation statements)

References 75 publications

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“…Our results are also consistent with the previous study. 49 We further note that the calculated band structure agrees with the ARPES results ( Fig. 3 in Ref.…”

Section: Interaction Induced Interface States: Silicene Onsupporting

confidence: 83%

Layer k -projection and unfolding electronic bands at interfaces

Chen

Weinert

2018

Phys. Rev. B

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The k-projection method provides an approach to separate the contributions from different constituents in heterostructure systems, and can act as an aid to connect the results of experiments and calculations. We show that the technique can be used to "unfold" the calculated electronic bands of interfaces and supercells, and provide local band structure by integrating the projected states over specified regions of space, a step that can be implemented efficiently using fast Fourier transforms. We apply the method to investigate the effects of interfaces in heterostructures consisting of a graphene bilayer on H-saturated SiC(0001), BAs monolayer on the ferromagnetic semiconductor CrI3, silicene on Ag(111), and to the Bi2Se3 surface. Our results reveal that the band structure of the graphene bilayer around the Dirac point is strongly dependent on the termination of SiC (0001): on the C-face, the graphene is n-doped and a gap of ∼0.13 eV is opened, whereas on the Si-face, the graphene is essential unchanged and neutral. We show that for BAs/CrI3, the magnetic proximity effect can effectively induce a spin splitting up to about 50 meV in BAs. For silicene/Ag(111), our calculations reproduce the angle-resolved photoemission spectroscopy results, including linearly dispersing bands at the edge of the first Brillouin zone of Ag(111); although these states result from the interaction between the silicene overlayer and the substrate, we demonstrate that they are not Dirac states.

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“…Our results are also consistent with the previous study. 49 We further note that the calculated band structure agrees with the ARPES results ( Fig. 3 in Ref.…”

Section: Interaction Induced Interface States: Silicene Onsupporting

confidence: 83%

Layer k -projection and unfolding electronic bands at interfaces

Chen

Weinert

2018

Phys. Rev. B

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“…The Dirac band structure of free-standing stanene may be destroyed for the present system of epitaxial stanene on a Ag 2 Sn surface alloy. However, further experimental and theoretical studies, may reveal still unnoticed enticing properties, such as the actual presence of interaction induced Dirac cones at previously insufficiently explored regions of the band structure, as has been revealed recently for epitaxial silicene on Ag (1 1 1) [32,33], which was considered before as loosing its most exciting properties [34]. We also recall that structural flatness of stanene is predicted to drive RT QSH effects [19].…”

Section: Electronic Band Structurementioning

confidence: 57%

Large area planar stanene epitaxially grown on Ag(1 1 1)

et al. 2018

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Artificial post-graphene elemental 2D materials have received much attention recently. Especially, stanene, the tin analogue of graphene, is expected to be a robust 2D topological insulator, even above room temperature. We have grown epitaxial 2D stanene on a Ag(1 1 1) single crystal template and determined its crystalline structure synergetically by scanning tunneling microscopy, high-resolution synchrotron radiation photoemission spectroscopy, and advanced first principles calculations. From the STM images, we show that stanene forms a nearly planar structure in large domains. A detailed core-level spectroscopy analysis as well as DFT calculations reveal that the stanene sheet lays over an ordered 2D Ag2Sn surface alloy, but not directly on a bulk-terminated Ag(1 1 1) surface. The electronic structure exhibits a characteristic 2D band with parabolic dispersion due to the non-negligible interaction with the underlying surface alloy.

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“…Brillouin zone (BZ) was sampled using Monkhorst-Pack scheme [107] with a 6 × 6 × 3 k-point mesh. Band unfolding techniques were utilized to generate the effective band structure (EBS) [108,109] with a modified version of BandUP code [110][111][112]. Onsite Coulomb repulsion U = 3.5 eV was added to the Ti atom to reproduce the experimental band structure, while we used U = 0 in the dynamic TDDFT calculations and structural optimization.…”

Section: Methodsmentioning

confidence: 99%

Ultrafast charge ordering by self-amplified exciton–phonon dynamics in TiSe2

Lian

Zhang

et al. 2020

Nat Commun

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The origin of charge density waves (CDWs) in TiSe has long been debated, mainly due to the difficulties in identifying the timescales of the excitonic pairing and electron–phonon coupling (EPC). Without a time-resolved and microscopic mechanism, one has to assume simultaneous appearance of CDW and periodic lattice distortions (PLD). Here, we accomplish a complete separation of ultrafast exciton and PLD dynamics and unravel their interplay in our real-time time-dependent density functional theory simulations. We find that laser pulses knock off the exciton order and induce a homogeneous bonding–antibonding transition in the initial 20 fs, then the weakened electronic order triggers ionic movements antiparallel to the original PLD. The EPC comes into play after the initial 20 fs, and the two processes mutually amplify each other leading to a complete inversion of CDW ordering. The self-amplified dynamics reproduces the evolution of band structures in agreement with photoemission experiments. Hence we resolve the key processes in the initial dynamics of CDWs that help elucidate the underlying mechanism.

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Dirac cone pairs in silicene induced by interface Si-Ag hybridization: A first-principles effective band study

Cited by 21 publications

References 75 publications

Layer k -projection and unfolding electronic bands at interfaces

Layer k -projection and unfolding electronic bands at interfaces

Large area planar stanene epitaxially grown on Ag(1 1 1)

Ultrafast charge ordering by self-amplified exciton–phonon dynamics in TiSe2

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