Mapping polarization induced surface band bending on the Rashba semiconductor BiTeI

Butler, C. J.; Yang, Hung-Hsiang; Hong, Jhen-Yong; Hsu, Shih-Hao; Sankar, Raman; Lu, Chien-Rong; Lu, Hsin-yu; Yang, Kaimin; Shiu, Hung-Wei; Chen, Chia-Hao; Kaun, Chao-Cheng; Shu, G. J.; Chou, F. C.; Lin, Minn-Tsong

doi:10.1038/ncomms5066

Cited by 40 publications

(37 citation statements)

References 21 publications

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“…Owing to the presence of both domain types in the bulk, the natural cleavage plane between Te and I layers exposes Te- and I-terminated areas on the same surface. Both terminations occur to the same extent on the sample surface with domain widths of 10–100 nm (refs 19 , 28 , 29 ). The momentum microscope employed for our experiments probes a sample area of ∼20 μm in diameter.…”

Section: Resultsmentioning

confidence: 99%

“…The resulting electric polarization along the layer stacking axis facilitates a giant Rashba effect in the electronic structure of BiTeI and related materials 14 15 16 17 . It also gives rise to a pronounced n-type or p-type band bending at the surface in dependence of the nominal charge of the terminating atomic layer 18 19 . This makes it possible to place either valence or conduction band states at the Fermi level by choice of the surface termination 18 .…”

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confidence: 99%

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Spin-texture inversion in the giant Rashba semiconductor BiTeI

et al. 2016

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Semiconductors with strong spin–orbit interaction as the underlying mechanism for the generation of spin-polarized electrons are showing potential for applications in spintronic devices. Unveiling the full spin texture in momentum space for such materials and its relation to the microscopic structure of the electronic wave functions is experimentally challenging and yet essential for exploiting spin–orbit effects for spin manipulation. Here we employ a state-of-the-art photoelectron momentum microscope with a multichannel spin filter to directly image the spin texture of the layered polar semiconductor BiTeI within the full two-dimensional momentum plane. Our experimental results, supported by relativistic ab initio calculations, demonstrate that the valence and conduction band electrons in BiTeI have spin textures of opposite chirality and of pronounced orbital dependence beyond the standard Rashba model, the latter giving rise to strong optical selection-rule effects on the photoelectron spin polarization. These observations open avenues for spin-texture manipulation by atomic-layer and charge carrier control in polar semiconductors.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Spin-texture inversion in the giant Rashba semiconductor BiTeI

et al. 2016

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“…On the contrary, BiTeI has a multi-domain (001) surface with coexisting Te-and I-terminations on the scale of 100 nm. 11,[67][68][69] Consequently, BiTeBr is believed to be the most homogeneous of all BiTeX tellurohalides and a well-suited candidate for future spintronic applications. We also did not observe any signs of stacking disorder, domains or flipped layers in BiTeBr.…”

Section: Crystal Structure Of Bimentioning

confidence: 99%

Synthesis, Crystal and Topological Electronic Structures of New Bismuth Tellurohalides Bi₂TeBr and Bi₃TeBr

et al. 2018

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Halogen substitution, i. e. bromine for iodine, in the series of topological Bi n TeI (n = 1, 2, 3) materials is conducted in order to explore an impact of anion exchange on the topological electronic structure. In the proof-of-concept study we demonstrate the applicability of the modular view on the crystal and electronic structures of the new Bi 2 TeBr and Bi 3 TeBr compounds. Along with the isostructural telluroiodides, they constitute a family of layered structures that are stacked from two basic building modules, [ ஶ ଶ Bi 2 ] and [ ஶ ଶ BiTeX] (X = I, Br). We present solid-state synthesis, thermochemical studies, crystal growth and crystal-structure elucidation of Bi 2 TeBr (sp.gr. R3 തm (no. 166), a = 433.04(2) pm, c = 5081.6(3) pm) and Bi 3 TeBr (sp.gr. R3m (no. 160), a = 437.68(3) pm, c = 3122.9(3) pm). First-principles calculations establish the topological nature of Bi 2 TeBr and Bi 3 TeBr. General aspects of chemical bonding appear to be similar for Bi n TeX (X = I, Br) with the same n, so that the alternation of the global gap size upon substitution is insignificant. The complex topological inversion proceeds between the states of two distinct modules, [ ஶ ଶ Bi 2 ] and [ ஶ ଶ BiTeBr]; thus, the title compounds can be seen as heterostructures built via a modular principle. Furthermore, highly disordered as well as incommensurately modulated ternary phase(s) are documented near the Bi 2 TeBr composition. Single-crystal X-ray diffraction experiments on BiTeBr and Bi 2 TeI resolve some discrepancies in the prior published work.

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“…suggest that the breaking translational symmetry at the surface with the strong ionicity modifies the electrostatic potential near the surface 17 . In contrast to these surface origins, Butler et al speculate that the spontaneous electric polarization in the bulk causes the spectral shift to discuss the surface structures 18 . Actually, the surface structure necessary to identify the origin is also still obscure.…”

Section: Introductionmentioning

confidence: 99%

Imaging ambipolar two-dimensional carriers induced by the spontaneous electric polarization of a polar semiconductor BiTeI

et al. 2015

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Two-dimensional (2D) mobile carriers are a wellspring of quantum phenomena. Among various 2D-carrier systems, such as field effect transistors and heterostructures, polar materials hold a unique potential; the spontaneous electric polarization in the bulk could generate positive and negative 2D carriers at the surface. Although several experiments have shown ambipolar carriers at the surface of a polar semiconductor BiTeI, their origin is yet to be specified. Here we provide compelling experimental evidences that the ambipolar 2D carriers at the surface of BiTeI are induced by the spontaneous electric polarization. By imaging electron standing waves with spectroscopic imaging scanning tunneling microscopy, we find that positive or negative carriers with Rashba-type spin splitting emerge at the surface correspondingly to the polar directions in the bulk. The electron densities at the surface are constant independently of those in the bulk, corroborating that the 2D carriers are induced by the spontaneous electric polarization. We also successfully image that lateral p-n junctions are formed along the boundaries of submicron-scale domains with opposite polar directions. Our study presents a novel means to endow non-volatile, spin-polarized, and ambipolar 2D carriers as well as, without elaborate fabrication, lateral p-n junctions of those carriers at atomically-sharp interfaces.

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Mapping polarization induced surface band bending on the Rashba semiconductor BiTeI

Cited by 40 publications

References 21 publications

Spin-texture inversion in the giant Rashba semiconductor BiTeI

Spin-texture inversion in the giant Rashba semiconductor BiTeI

Synthesis, Crystal and Topological Electronic Structures of New Bismuth Tellurohalides Bi₂TeBr and Bi₃TeBr

Imaging ambipolar two-dimensional carriers induced by the spontaneous electric polarization of a polar semiconductor BiTeI

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Mapping polarization induced surface band bending on the Rashba semiconductor BiTeI

Cited by 40 publications

References 21 publications

Spin-texture inversion in the giant Rashba semiconductor BiTeI

Spin-texture inversion in the giant Rashba semiconductor BiTeI

Synthesis, Crystal and Topological Electronic Structures of New Bismuth Tellurohalides Bi2TeBr and Bi3TeBr

Imaging ambipolar two-dimensional carriers induced by the spontaneous electric polarization of a polar semiconductor BiTeI

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Synthesis, Crystal and Topological Electronic Structures of New Bismuth Tellurohalides Bi₂TeBr and Bi₃TeBr