Coverage dependence of the Fe-induced Fermi-level shift and the two-dimensional electron gas on InAs(110)

Morgenstern, Markus; Getzlaff, M.; Haude, D.; Wiesendanger, R.; Johnson, Robert L.

doi:10.1103/physrevb.61.13805

Cited by 40 publications

(44 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The negative Θ-dependence of N s was also observed at InAs cleaved surfaces for Agcoverage of Θ ≥ 0.04 ML [3,4]. It is consistent with the negative coverage dependence of the Fermi energy observed in photoelectron and electron-energy-loss spectroscopy measurements on cleaved surfaces of InAs and InSb with various kinds of adsorbed materials [9][10][11][12][13][14][15][16][17][18][19][20][21]. The Fermi energy ε F is considered to be at an adsorbateinduced surface donor level located in the conduction band except in the very low-Θ region where the donors are fully ionized [3,4,22].…”

supporting

confidence: 72%

Quantum Hall effect at cleaved InSb surfaces and low-temperature annealing effect

Masutomi

Hio

Mochizuki

et al. 2007

Applied Physics Letters

View full text Add to dashboard Cite

We have performed low-temperature in-plane magnetotransport measurements on twodimensional electron systems induced by deposition of Ag at in situ cleaved surfaces of p-type InSb. The quantum Hall effect was observed even at low magnetic fields around 2 T. The surface electron density and the electron mobility exhibit strong dependence on the Ag-coverage and the annealing temperature in the range of 15-40 K. The annealing effect suggests that the surface morphology strongly affects the properties of the two-dimensional electron systems.A two-dimensional electron system (2DES) at low temperatures and in a strong magnetic field shows the quantum Hall (QH) effect, in which the diagonal resistivity ρ xx vanishes and the Hall resistance is quantized as R H = h/ie 2 for an integer i [1, 2]. Recently, Tsuji et al. performed in-plane magnetotransport measurements on 2DESs induced by deposition of Ag atoms at in situ cleaved surfaces of p-type InAs and observed the QH effect for i = 4 [3,4]. However, a high magnetic field above 10 T was required for the observation of the QH effect. For future research on microscopic current distribution, such as edge channel transport, surface QH systems that can be observed at low magnetic fields are desirable to reduce the difficulty of constructing an experimental system with a scanning microscope. The integer QH effect is expected to appear in the region where the Landau level separationhω c exceeds the level broadeninghτ(ω c τ > 1). Here, ω c is the cyclotron frequency and τ is the scattering time. The dimensionless parameter ω c τ is equivalent to the product of B and the electron mobility µ. It is well-known that InSb has a very small electron effective mass m * = 0.013m e at the Γ point, where m e is the free-electron mass. This value is about a half of that in InAs (m * = 0.026m e ) and thus higher electron mobility (µ = eτ /m * ) is expected. In this letter, we report the observation of the QH effect at cleaved surfaces of InSb. The quantized Hall resistance and the vanishing of ρ xx were clearly observed even at low magnetic fields around 2 T. Besides the dependence on the coverage of adsorbed Ag atoms, annealing effect was studied in the range of 15-40 K. The results suggest that the surface morphology strongly affects the properties of 2DESs.The samples used were cut from a Ge-doped single crystal with an acceptor concentration of 1-2 × 10 21 m −3 . In the case of p-type crystals, the surface electrons are separated from the three-dimensional carriers in the substrate by the depletion layer. Sample preparation and experimental setup are similar to those used in the previous work on InAs surfaces [3,4]. Sample cleaving was done at low temperatures in an ultra-high vacuum chamber with a 4 He cryostat. Magnetotranport data on the (110) cleaved surface were taken in a Hall bar geometry (4 mm × 0.4 mm) using the standard four-probe lock-in technique at 13 Hz with two current electrodes and four voltage electrodes prepared by deposition of gold films onto noncleaved surfaces at r...

show abstract

supporting

confidence: 72%

Quantum Hall effect at cleaved InSb surfaces and low-temperature annealing effect

Masutomi

Hio

Mochizuki

et al. 2007

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…Previous ARUPS measurements revealed the coverage dependence of the adsorbate induced band shift and a rough estimate of the 2DES subband energies E n [4]. With the high resolution of the ASPHERE analyzer, individual subband peaks are resolved (Fig.…”

mentioning

confidence: 96%

“…It shows several Fe atoms (dark dots), but no correspondence between the Fe positions and the measured potential. This might be surprising, since the adsorbate layer donates electrons to the 2DES and is thus charged [4]. Anyway, in the area of Fig.…”

mentioning

confidence: 99%

“…In fact, only one study deals with the spatial distribution of the 2DES LDOS, which, however, reveals little quantitative information, because neither the exact subband energies nor the disorder potential were known [3]. Here, we investigate the LDOS of the adsorbate induced 2DES on InAs(110) [4] by scanning tunneling spectroscopy (STS). Subband energies are determined by angle-resolved photoelectron spectroscopy (ARUPS) and the 2DES potential landscape is measured using the lowest state of the tip induced quantum dot (QD) [5].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Direct Comparison between Potential Landscape and Local Density of States in a Disordered Two-Dimensional Electron System

Morgenstern¹,

Klijn²,

Meyer³

et al. 2002

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Submonolayer depositions of alkali and transition metals can also lead to an electron accumulation layer in InAs. [11][12][13] Metal deposition on a clean InN surface allows the energy level position of the Fermi level to be spectroscopically distinguished in photoemission measurements. An electron accumulation layer can be inferred if the E F lies higher in energy than the conduction band minimum.…”

mentioning

confidence: 99%

X-ray photoemission spectroscopic investigation of surface treatments, metal deposition, and electron accumulation on InN

Rickert

Ellis

Himpsel

et al. 2003

Applied Physics Letters

View full text Add to dashboard Cite

The effects of surface chemical treatments and metal deposition on the InN surface are studied via synchrotron-based photoemission spectroscopy. Changes in the In 4d core level as well as the valence band spectra are reported. The surface Fermi level position, E F , relative to the valence band maximum was determined for both Au and Ti Schottky barriers. E F lies at an energy of 0.7 eV above the valence band maximum for Au deposited on annealed InN and 1.2 eV above the valence band maximum for Ti deposited on Ar-sputtered InN. These results that the surface Fermi level lays at or above the conduction band maximum when a value of InN band gap of 0.7-0.9 eV is assumed.

show abstract

Coverage dependence of the Fe-induced Fermi-level shift and the two-dimensional electron gas on InAs(110)

Cited by 40 publications

References 33 publications

Quantum Hall effect at cleaved InSb surfaces and low-temperature annealing effect

Quantum Hall effect at cleaved InSb surfaces and low-temperature annealing effect

Direct Comparison between Potential Landscape and Local Density of States in a Disordered Two-Dimensional Electron System

X-ray photoemission spectroscopic investigation of surface treatments, metal deposition, and electron accumulation on InN

Contact Info

Product

Resources

About