Local potentiometry using a multiprobe scanning tunneling microscope

Bannani, A; Bobisch, C. A.; Möller, R.

doi:10.1063/1.2968111

Cited by 58 publications

(88 citation statements)

References 44 publications

(31 reference statements)

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“…However, such devices can be further extended with scanning tunneling potentiometry (STP) techniques which allow to map the electric potential on the nanoscale with spatial and potential resolution of few Å and µV, respectively. [4][5][6] Combination of STP with multiprobe point measurements creates a powerful tool for the electrical sample characterization capable to give insight into fundamental transport properties, such as the influence of defects on the local electric transport. This applies especially for surface dominated transport as present, e.g., in topological insulators and allows the investigation of transport phenomena such as the Landauer dipole.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] The most common experiments reported in the literature using those instruments are multi-probe measurements that allow to determine the microscopic electrical properties of the samples under investigation. However, such devices can be further extended with scanning tunneling potentiometry (STP) techniques which allow to map the electric potential on the nanoscale with spatial and potential resolution of few Å and µV, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Scanning tunneling potentiometry implemented into a multi-tip setup by software

Lüpke

Korte

Cherepanov

et al. 2015

Review of Scientific Instruments

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We present a multi-tip scanning tunneling potentiometry technique that can be implemented into existing multi-tip scanning tunneling microscopes without installation of additional hardware. The resulting setup allows flexible in situ contacting of samples under UHV conditions and subsequent measurement of the sample topography and local electric potential with resolution down to Å and μV, respectively. The performance of the potentiometry feedback is demonstrated by thermovoltage measurements on the Ag/Si(111)−(3×3)R30∘ surface by resolving a standing wave pattern. Subsequently, the ability to map the local transport field as a result of a lateral current through the sample surface is shown on Ag/Si(111)−(3×3)R30∘ and Si(111) − (7 × 7) surfaces.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Scanning tunneling potentiometry implemented into a multi-tip setup by software

Lüpke

Korte

Cherepanov

et al. 2015

Review of Scientific Instruments

View full text Add to dashboard Cite

show abstract

“…Since the most popular 2D semiconductors have isotropic low-energy dispersion, Fermi surface matching can be satisfied by appropriately tuning the Fermi energy, so that the hidden quantum mirage can be detected by the well-developed multiprobe scanning tunneling microscopy (STM), which has already been used to characterize the non-local responses of many systems [30] such as two-dimensional thin films [31] and graphene [32,33] with nanoscale resolution. We consider a twodimensional PNJ connected to two STM tips, one located at R 1 in the N region and the other at R 2 in the P region.…”

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confidence: 99%

Hidden quantum mirage by negative refraction in semiconductor P-N junctions

Zhang¹,

Zhu²,

Yang³

et al. 2016

Phys. Rev. B

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We predict a novel quantum interference based on the negative refraction across a semiconductor P-N junction: with a local pump on one side of the junction, the response of a local probe on the other side behaves as if the disturbance emanates not from the pump but instead from its mirror image about the junction. This phenomenon is guaranteed by translational invariance of the system and matching of Fermi surfaces of the constituent materials, thus it is robust against other details of the junction (e.g., junction width, potential profile, and even disorder). The recently fabricated P-N junctions in 2D semiconductors provide ideal platforms to explore this phenomenon and its applications to dramatically enhance charge and spin transport as well as carrier-mediated long-range correlation.PACS numbers: 73.40. Lq, 75.30.Hx, 72.80.Vp Half a century ago, Veselago proposed the concept of negative refraction for electromagnetic waves [1][2][3][4]: upon transition from a medium with positive refractive index across a sharp interface into a negative index medium, a diverging pencil of rays is coherently refocused to form a sharp image or "quantum mirage" [5], similar to the bending of light to create mirages in the atmosphere. In the past decade, negative refraction and mirage have been observed for electromagnetic waves of various frequencies (see Ref.[6] for a review) and for cold atoms [7,8]. In 2007, Cheianov et al. [9] proposed the interesting idea that a sharp P-N junction of graphene can exhibit negative refraction and hence focus electrons out of a local pump into a sharp quantum mirage. This effect has been widely used in theoretical proposals to control charge and/or spin transport for massless Dirac fermions in semiconductors (see for a few examples). However, a sharp quantum mirage requires the junction to be sharp compared with the electron wavelength (∼ a few nanometers), otherwise it would disappear due to the path-dependent phase accumulation inside the junction. This makes the observation and application of this effect an experimentally challenging task [13].In this letter, we theoretically demonstrate that in many situations where the quantum mirage is no longer visible, its effect still exists, which could make the response across the P-N junction independent of distance. As a basic observation in physics, the response amplitude in a d-dimensional uniform system decays at least as fast as 1/R (d−1)/2 with distance R, irrespective of the energy dispersion, spin-orbit coupling, etc. This directly leads to rapid decay of many physical properties, such as the charge and spin conductivity [14] As an example, we demonstrate that the P-N junction could dramatically enhance the carriermediated long-range interaction between localized magnetic moments by several orders of magnitudes.For an intuitive physical picture about the hidden quantum mirage, we start from a sharp P-N junction as shown in Fig. 1(a). Here the plane waves excited by a local pump (filled red circle) in the N region is perfectly focuse...

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“…In this case, the voltage noise in potentiometry is dominated by thermal noise that is ΔV ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 4k B TR T Δf p , where Δf is the bandwidth [22]. A resolution better than 10 μV can be achieved at low temperatures [23].…”

Section: Experiments a Experimental Methodsmentioning

confidence: 99%

Energy Gap Induced by Friedel Oscillations Manifested as Transport Asymmetry at Monolayer-Bilayer Graphene Boundaries

Clark

Zhang

et al. 2014

Phys. Rev. X

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We show that Friedel charge oscillation near an interface opens a gap at the Fermi energy for electrons with wave vectors perpendicular to the interface. If the Friedel gaps on two sides of the interface are different, a nonequilibrium effect-shifting of these gaps under bias-leads to asymmetric transport upon reversing the bias polarity. The predicted transport asymmetry is revealed by scanning tunneling potentiometry at monolayer-bilayer interfaces in epitaxial graphene on SiC(0001). This intriguing interfacial transport behavior opens a new avenue toward novel quantum functions such as quantum switching.

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Local potentiometry using a multiprobe scanning tunneling microscope

Cited by 58 publications

References 44 publications

Scanning tunneling potentiometry implemented into a multi-tip setup by software

Scanning tunneling potentiometry implemented into a multi-tip setup by software

Hidden quantum mirage by negative refraction in semiconductor P-N junctions

Energy Gap Induced by Friedel Oscillations Manifested as Transport Asymmetry at Monolayer-Bilayer Graphene Boundaries

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