Quantization and topological states in the spin Hall conductivity of low-dimensional systems: An<i>ab initio</i>study

Matthes, Lars; Küfner, Sebastian; Furthmüller, J.; Bechstedt, F.

doi:10.1103/physrevb.93.121106

Cited by 17 publications

(31 citation statements)

References 30 publications

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“…In this section we investigate the spin Hall conductivity of the buckled monolayers. We note that earlier works in the literature have calculated the spin Hall conductivity of germanene [46] and stanene [47] at the Fermi level. We go a step further by including silicene and plumbene in our calculations as well as providing results for a wide range of energies with and without the perpendicular electric field.…”

Section: Spin Hall Conductivitymentioning

confidence: 81%

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Spin splitting and spin Hall conductivity in buckled monolayers of the group 14: First-principles calculations

Farzaneh,

Rakheja

2020

Preprint

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Elemental monolayers of the group 14 with a buckled honeycomb structure, namely silicene, germanene, stanene, and plumbene, are known to demonstrate a spin splitting as a result of an electric field parallel to their high symmetry axis which is capable of tuning their topological phase between a quantum spin Hall insulator and an ordinary band insulator. We perform first-principles calculations based on the density functional theory to quantify the spin-dependent band gaps and the spin splitting as a function of the applied electric field and extract the main coefficients of the invariant Hamiltonian. Using the linear response theory and the Wannier interpolation method, we calculate the spin Hall conductivity in the monolayers and study its sensitivity to an external electric field. Our results show that the spin Hall conductivity is not quantized and in the case of silicene, germanene, and stanene degrades significantly as the electric field inverts the band gap and brings the monolayer into the trivial phase. The electric field induced band gap does not close in the case of plumbene which shows a spin Hall conductivity that is robust to the external electric field.

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Section: Spin Hall Conductivitymentioning

confidence: 81%

“…[2] includes the relativistic spin-orbit coupling effects. Ab initio studies [46,47] on the spin Hall conductivity of germanene and stanene have only recently become available. Here, we go a step further by analyzing the electronic properties of all the monolayers: silicene, germanene, stanene, and plumbene.…”

Section: Introductionmentioning

confidence: 99%

Spin splitting and spin Hall conductivity in buckled monolayers of the group 14: First-principles calculations

Farzaneh,

Rakheja

2020

Preprint

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“…Because of the absence of inversion symmetry, we apply the method of Yu et al . 47 based on the evolution of the charge centers of the Wannier functions (WCC) between two time-reversal invariant momenta (TRIM) of the BZ 46 , 48 and implemented in the VASP code 18 , 49 . The topological invariant Z 2 is determined by the crossings of an arbitrary reference line modulo 2 connecting two TRIM points within the WCC phase evolution along the k y line 47 .…”

Section: Resultsmentioning

confidence: 99%

“…Although some lines in the WCC evolution appear to interconnect, the topological behavior is not clear. For germanene/graphene the presence of pair switchings simply give a topological invariant , which suggests that this system is a QSH phase 18 , 46 , 49 .…”

Section: Resultsmentioning

confidence: 99%

“…The linearly dispersive bands of the Dirac cones give rise to a constant optical absorbance, determined by the Sommerfeld finestructure constant 15 . The spin-orbit interaction opens a fundamental gap in the 2D honeycomb group-IV materials 15 – 18 . They are quantum spin Hall (QSH) insulators 6 , 16 – 19 with a quantized spin Hall conductivity 18 .…”

Section: Introductionmentioning

confidence: 99%

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Deposition of topological silicene, germanene and stanene on graphene-covered SiC substrates

Matusalem

Koda

Bechstedt

et al. 2017

Sci Rep

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Growth of X-enes, such as silicene, germanene and stanene, requires passivated substrates to ensure the survival of their exotic properties. Using first-principles methods, we study as-grown graphene on polar SiC surfaces as suitable substrates. Trilayer combinations with coincidence lattices with large hexagonal unit cells allow for strain-free group-IV monolayers. In contrast to the Si-terminated SiC surface, van der Waals-bonded honeycomb X-ene/graphene bilayers on top of the C-terminated SiC substrate are stable. Folded band structures show Dirac cones of the overlayers with small gaps of about 0.1 eV in between. The topological invariants of the peeled-off X-ene/graphene bilayers indicate the presence of topological character and the existence of a quantum spin Hall phase.

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Beyond graphene: Clean, hydrogenated and halogenated silicene, germanene, stanene, and plumbene

Bechstedt

Gori

Pulci

2021

Progress in Surface Science

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Quantization and topological states in the spin Hall conductivity of low-dimensional systems: Anab initiostudy

Cited by 17 publications

References 30 publications

Spin splitting and spin Hall conductivity in buckled monolayers of the group 14: First-principles calculations

Spin splitting and spin Hall conductivity in buckled monolayers of the group 14: First-principles calculations

Deposition of topological silicene, germanene and stanene on graphene-covered SiC substrates

Beyond graphene: Clean, hydrogenated and halogenated silicene, germanene, stanene, and plumbene

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