Inequivalent sites for Hg at the HgTe(110) surface

Yu, Xiaohua; Vanzetti, L.; Haugstad, Greg; Raisanen, A.; Franciosi, A.

doi:10.1016/0039-6028(92)90652-m

Cited by 6 publications

(3 citation statements)

References 42 publications

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“…The crystals were cut into pieces of 3ϫ3ϫ2 mm 3 size and were cleaved in an ultrahigh vacuum by the anvil and wedge technique along the ͑110͒ surface, at liquid nitrogen temperature with flat surfaces. As was pointed out by Yu et al, 11 extrinsic surface core level shifts at the spin-orbit split Hg5d bands can be observed in photoemission spectra in the case of poor cleavage. We never observed this effect in our spectra, so it is concluded that our samples always had good surface quality.…”

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confidence: 53%

Direct evidence for the inverted band structure of HgTe

et al. 2000

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Angular-resolved photoemission measurements of the nonpolar ͑110͒-cleavage face of HgTe single crystals have been performed along the ⌺ line to determine details of the band structure near the valence band maximum ͑VBM͒. Three bands are observed between VBM and 1 eV binding energy, instead of the two observed for a positive energy gap semiconductor CdTe. Their energy separations and positions relative to the Fermi energy are investigated at the ⌫ point and at slightly off-normal emission, applying room and low temperature of 40 K. In contrast to the heavily debated results of HgSe ͓K.-U. Gawlik et al., Phys. Rev. Lett. 78, 3165 ͑1997͔͒ the clear observations for HgTe are consistent with the model of an inverted band structure, reflecting a semiconductor with a negative band gap.

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confidence: 53%

Direct evidence for the inverted band structure of HgTe

et al. 2000

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“…The experimental position of the Fermi level with respect to the VBM is of particular interest in order to distinguish between metallic and semiconducting band structures. It has, however, only been reported for HgTe(110) by Yu et al [11]. They determined the Fermi level to be 0.59 eV above the VBM.…”

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“…Photoemission results on HgSe and HgTe [11][12][13][14][15], in contrast, exhibit larger valence band widths of about 5.0-5.8 eV. The experimental position of the Fermi level with respect to the VBM is of particular interest in order to distinguish between metallic and semiconducting band structures.…”

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confidence: 99%

HgSe: Metal or Semiconductor?

et al. 1997

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From magnetotransport measurements it is generally believed that Hg-VI compounds show zero gap semiconducting behavior. Applying combined angle-resolved photoemission and inverse photoemission spectroscopy on HgSe(001) c͑2 3 2͒, we observe a positive fundamental gap of about 0.42 eV and a surface related state close to the Fermi level above the conduction band minimum. Following the results of this direct determination of the k-resolved band structure, previous experiments favoring zero gap models of Hg-VI compounds need to be reinterpreted. [S0031-9007 (97)03026-3] PACS numbers: 73.20.At, 79.60.BmBecause of its technological interest for electro-optical devices, the Zn and Cd containing II-VI compound semiconductors have been studied intensively over the past decade. The group of Hg containing II-VI compounds, however, has been scarcely investigated since its electronic structures were reported to reveal zero or even negative fundamental gaps with inverted band structures. Following results on a-Sn from Groves and Paul [1], the valence band maximum (VBM) was considered to be degenerate with the conduction band minimum (CBM) revealing G 8 symmetry. Early magnetotransport measurements measuring extremal cross sections of Fermi surfaces indeed found evidence for an inverted band structure in bulk HgSe [2-4] similar to those observed on HgTe [5] and b-HgS [6].Semiempirical band structure calculations for HgSe [7-9] and HgTe [7,8,10] fitting those data, consequently, show an inverted band structure with valence band widths of the order of 3.3-4.4 eV for HgSe and 3.6-4.8 eV for HgTe, respectively. Photoemission results on HgSe and HgTe [11][12][13][14][15], in contrast, exhibit larger valence band widths of about 5.0-5.8 eV. The experimental position of the Fermi level with respect to the VBM is of particular interest in order to distinguish between metallic and semiconducting band structures. It has, however, only been reported for HgTe(110) by Yu et al. [11]. They determined the Fermi level to be 0.59 eV above the VBM. Infrared absorption data [16,17] show two absorption edges around 0.4 and 0.2 eV photon energy which are interpreted as transitions from the two upper valence bands near G 8 and G 6 into the G 8 conduction band, leading to a fundamental energy gap of approximately 20.2 eV.The experimental results, together with the semiempirical band structure calculations reported so far, do not give a consistent picture of the band structure around the Fermi level of Mercury containing II-VI compounds. This can be attributed to the type of experiments giving only indirect information on band structures (optical and magnetotransport measurements) and theories fitting these data.In this Letter we take HgSe as the prototype material of Hg-VI compounds which, in addition, may be compared to the better-known narrow gap semiconductor InAs having a similar lattice constant. We report on direct measurements of the k-resolved occupied and unoccupied band structure around the Fermi level of HgSe(001) c͑2 3 2͒ by means of comb...

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In Situ Processing by Gas or Alkali Metal Dosing and by Cleavage

Pianetta

2002

Specimen Handling, Preparation, and Treatments in Surface Characterization

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Inequivalent sites for Hg at the HgTe(110) surface

Cited by 6 publications

References 42 publications

Direct evidence for the inverted band structure of HgTe

Direct evidence for the inverted band structure of HgTe

HgSe: Metal or Semiconductor?

In Situ Processing by Gas or Alkali Metal Dosing and by Cleavage

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