Conductivity of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mtext>Si</mml:mtext><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>111</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mn>7</mml:mn><mml:mo>×</mml:mo><mml:mn>7</mml:mn></mml:mrow></mml:math>dangling-bond state

D’Angelo, M.; Takase, Keiko; Miyata, Nobuhiro; Hirahara, Toru; Hasegawa, Shuji; Nishide, Akinori; Ogawa, M.; Matsuda, Iwao

doi:10.1103/physrevb.79.035318

Cited by 33 publications

(25 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We calculated a conductivity of σ c = (2.7 ± 0.4) × 10 −6 −1 −1 . Following the Ioffe-Regel condition, 14 the absolute value of the calculated conductivity is close to a metallic system (σ = 3.83 × 10 −5 −1 −1 ), in agreement with some of the measurements described in the literature 15,16 that classify the Si-7 × 7 surface as a good conductor. In a subsequent theoretical and experimental study we will endeavour to separate surface state conduction from contributions, space-charge, and bulk conduction.…”

Section: Potential Profile Of a Si(111)-7 × 7 Surfacesupporting

confidence: 80%

Four-probe measurements with a three-probe scanning tunneling microscope

Salomons

Martins

Zikovsky

et al. 2014

Review of Scientific Instruments

View full text Add to dashboard Cite

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

show abstract

Section: Potential Profile Of a Si(111)-7 × 7 Surfacesupporting

confidence: 80%

Four-probe measurements with a three-probe scanning tunneling microscope

Salomons

Martins

Zikovsky

et al. 2014

Review of Scientific Instruments

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5] Of particular interest is the Si(111)-7 × 7 reconstructed surface, which has metallic conducting properties despite bulk Si being a semiconductor. 6 This phenomenon must be well understood in order to reliably control and exploit this property in future electronic devices.…”

Section: Introductionmentioning

confidence: 99%

“…2 This uncertainty is attributed to the sensitivity to the sample quality and limitations of experimental techniques. Computational studies on the 7 × 7 reconstruction are also challenging due to its complex nature and sheer size.…”

Section: Introductionmentioning

confidence: 99%

Electronic properties of Si(111)-7×7and related reconstructions: Density functional theory calculations

Smeu

Guo

et al. 2012

Phys. Rev. B

View full text Add to dashboard Cite

The 7 × 7 reconstruction of Si(111) has the interesting property of being metallic despite bulk Si being a semiconductor. This surface has a complex reconstruction that takes on a dimer-adatom stacking fault (DAS) structure composed of adatoms, rest atoms, and several other key features. It is believed that the dangling bonds of the adatoms play a crucial role in the high conductivity and that this is predominantly a surface-state band effect. To elucidate the details of this mechanism, we investigate a set of related Si(111) reconstructions of increasing complexity in order to resolve the effect of the different DAS features on the electronic and transport properties of the Si(111)-7 × 7 surface. Density functional theory calculations are carried out on the √ 3 × √ 3-R30 • , 2 × 2, 5 × 5, and 7 × 7 reconstructions of Si(111). Since these surfaces are modeled as two-dimensional slabs, a careful investigation is carried out to determine the slab thickness needed to capture the structural and electronic properties of these systems. The densities of states (DOSs) projected on different atoms in these surfaces are then compared, revealing that the √ 3 × √ 3, 5 × 5, and 7 × 7 surfaces are metallic, while the 2 × 2 surface is semiconducting. Finally, the DOSs for Si(111)-7 × 7 are related to scanning tunneling microscope data to offer an explanation for different adatom prominence trends depending on Si sample doping.

show abstract

“…5 An intriguing question is how electrons propagate through the metallic surface state, which is still under discussion and we refer the reader to Refs. [6][7][8][9][10][11][12][13]. A popular description is that electrons, tunneling from a STM tip onto the surface, propagate along the metallic surface state before entering the bulk.…”

Section: Introductionmentioning

confidence: 99%

Localization of the phantom force induced by the tunneling current

2012

View full text Add to dashboard Cite

The phantom force is an apparently repulsive force, which can dominate the atomic contrast of an AFM image when a tunneling current is present. We described this effect with a simple resistive model, in which the tunneling current causes a voltage drop at the sample area underneath the probe tip. Because tunneling is a highly local process, the areal current density is quite high, which leads to an appreciable local voltage drop that in turn changes the electrostatic attraction between tip and sample. However, Si(111)-7×7 has a metallic surface state and it might be proposed that electrons should instead propagate along the surface state, as through a thin metal film on a semiconducting surface, before propagating into the bulk. In this paper, we first measure the phantom force on a sample that displays a metallic surface state [here, Si(111)-7×7] using tips with various radii. If the metallic surface state would lead to a constant electrostatic potential on the surface, we would expect a direct dependence of the phantom force with tip radius. In a second set of experiments, we study H/Si(100), a surface that does not have a metallic surface state. We conclude that a metallic surface state does not suppress the phantom force, but that the local resistance R s has a strong effect on the magnitude of the phantom force.

show abstract

Conductivity of theSi(111)7×7dangling-bond state

Cited by 33 publications

References 32 publications

Four-probe measurements with a three-probe scanning tunneling microscope

Four-probe measurements with a three-probe scanning tunneling microscope

Electronic properties of Si(111)-7×7and related reconstructions: Density functional theory calculations

Localization of the phantom force induced by the tunneling current

Contact Info

Product

Resources

About