Dirac Fermions in Borophene

Feng, Baojie; Sugino, Osamu; Liu, Ro-Ya; Zhang, Jin; Yukawa, Ryu; Kawamura, Masaya; Iimori, Takushi; Kim, Howon; Hasegawa, Yukio; Li, Hui; Chen, Lan; Wu, Kehui; Kumigashira, Hiroshi; Komori, Fumio; Chiang, T.‐C.; Meng, Sheng; Matsuda, Iwao

doi:10.1103/physrevlett.118.096401

Cited by 414 publications

(402 citation statements)

References 46 publications

(48 reference statements)

Supporting

Mentioning

372

Contrasting

Order By: Relevance

“…The conduction and valence bands in graphene touch with linear dispersion at discrete Dirac points on the Fermi level, around which the low-energy electrons behave like relativistic massless Dirac fermions in 2D, exhibiting properties distinct from the usual Schrödinger fermions. Inspired by graphene, much effort has been devoted to the search for other 2D materials which host Dirac/Weyl points, and a number of candidates have been proposed 3 , such as silicene 4,5 , germanene 4,6 , graphyne 7 , 2D carbon and boron allotropes [8][9][10][11][12] , group-VA phosphorene structures 13,14 , and 5d transition metal trichloride 15 . The Dirac points in all these materials (including graphene) are protected by symmetry, but only in the absence of spin-orbit coupling (SOC).…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional spin-orbit Dirac point in monolayer HfGeTe

Guan

Liu

et al. 2017

Phys. Rev. Materials

View full text Add to dashboard Cite

Dirac points in two-dimensional (2D) materials have been a fascinating subject of research, with graphene as the most prominent example. However, the Dirac points in existing 2D materials, including graphene, are vulnerable against spin-orbit coupling (SOC). Here, based on first-principles calculations and theoretical analysis, we propose a new family of stable 2D materials, the HfGeTefamily monolayers, which represent the first example to host so-called spin-orbit Dirac points (SDPs) close to the Fermi level. These Dirac points are special in that they are formed only under significant SOC, hence they are intrinsically robust against SOC. We show that the existence of a pair of SDPs are dictated by the nonsymmorphic space group symmetry of the system, which are very robust under various types of lattice strains. The energy, the dispersion, and the valley occupation around the Dirac points can be effectively tuned by strain. We construct a low-energy effective model to characterize the Dirac fermions around the SDPs. Furthermore, we find that the material is simultaneously a 2D Z2 topological metal, which possesses nontrivial Z2 invariant in the bulk and spin-helical edge states on the boundary. From the calculated exfoliation energies and mechanical properties, we show that these materials can be readily obtained in experiment from the existing bulk materials. Our result reveals HfGeTe-family monolayers as a promising platform for exploring spin-orbit Dirac fermions and novel topological phases in two-dimensions.

show abstract

Section: Introductionmentioning

confidence: 99%

Two-dimensional spin-orbit Dirac point in monolayer HfGeTe

Guan

Liu

et al. 2017

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…The possibility of having such topological states has triggered an enormous amount of interest in searching for new materials with Dirac dispersion. Among recent proposals for 2D Dirac materials such as borophene 3 , stanene 4 , and silicene 5 , the 2D semi-Dirac (SD) systems 6 seem to have many exotic and unusual properties 7,8 due to their anisotropic band dispersion: linear in one direction and parabolic along the perpendicular direction. Promising candidates for such semi-Dirac systems include TiO 2 /V 2 O 3 layered structures 9 , deformed graphene 10 , BEDT-TTF 2 I 3 salt under pressure 11 , hexagonal and square lattices in the presence of magnetic field 12,13 , photonic systems 14 , etc.…”

Section: Introductionmentioning

confidence: 99%

Interplay between topology and disorder in a two-dimensional semi-Dirac material

2018

View full text Add to dashboard Cite

We investigate the role of disorder in a two-dimensional semi-Dirac material characterized by a linear dispersion in one direction and a parabolic dispersion in the orthogonal direction. Using the self-consistent Born approximation, we show that disorder can drive a topological Lifshitz transition from an insulator to a semi metal, as it generates a momentum-independent off-diagonal contribution to the self-energy. Breaking time-reversal symmetry enriches the topological phase diagram with three distinct regimes-single-node trivial, two-node trivial, and two-node Chern. We find that disorder can drive topological transitions from both the single-and two-node trivial to the two-node Chern regime. We further analyze these transitions in an appropriate tight-binding Hamiltonian of an anisotropic hexagonal lattice by calculating the real-space Chern number. Additionally, we compute the disorder-averaged entanglement entropy which signals both the topological Lifshitz and Chern transition as a function of the anisotropy of the hexagonal lattice. Finally, we discuss experimental aspects of our results.

show abstract

“…As a result, a bigger nontrivial SOC gap in their Dirac cone is induced. [49][50][51] Besides, theoretical studies also indicated that borophene might possess Dirac Fermions [52] and exhibit superconductivity [53] at low temperatures. For example, it was reported that a nontrivial SOC gap of intrinsic stanene was over 30 meV.…”

Section: Current Status Of 2d Materials Researchmentioning

confidence: 99%

Computational Understanding of the Growth of 2D Materials

Gao

Chen

et al. 2018

Advcd Theory and Sims

View full text Add to dashboard Cite

Over the last two decades, remarkable progress has been made in use of computational methods for understanding 2D materials growth. The aim of this Review is to provide an overview of several state-of-the-art computational methods for the modelling and simulation of 2D materials growth. First, the current status of 2D materials, and their major growth methods are addressed. Next, the applications of the ab initio method in 2D materials growth is discussed, focusing on reaction of precursors, diffusion of adatoms, energetics and kinetics of growth fronts, and effects of substrates. Then, the applications of the molecular dynamics approach in 2D materials growth is discussed, with emphasis on the growth of graphene on various substrates and the growth of boron nitride and silicene. Furthermore, the applications of the kinetic Monte Carlo method in 2D materials growth are discussed. The parametrization of the method and its application in dimer distribution, and nonlinear edge growth of graphene are discussed. Subsequently, the applications of the phase-field method in 2D materials growth are discussed, focusing on the growth rate and morphological evolution of 2D domains. Finally, perspectives and conclusions are presented.

show abstract

Dirac Fermions in Borophene

Cited by 414 publications

References 46 publications

Two-dimensional spin-orbit Dirac point in monolayer HfGeTe

Two-dimensional spin-orbit Dirac point in monolayer HfGeTe

Interplay between topology and disorder in a two-dimensional semi-Dirac material

Computational Understanding of the Growth of 2D Materials

Contact Info

Product

Resources

About