Optimizing surface defects for atomic-scale electronics: Si dangling bonds

Scherpelz, Peter; Galli, Giulia

doi:10.1103/physrevmaterials.1.021602

Cited by 19 publications

(23 citation statements)

References 74 publications

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“…In contrast, the presence of two negatively charged DBs next to the neutral DB strongly shifts its charge transition to 395 mV (Supporting Figure S2f This is in agreement with (0/-) charge transition energies for Si(100)/SiO2 interface dangling bonds (Pb0 centers) 43 where a value of 0.27土0.1 eV was reported. We note that ab initio calculations report significantly lower values for the negative DB state than our obtained value 26,39,[44][45][46] . Figure 2q highlights that closely spaced DB pairs share a single negative charge.…”

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confidence: 78%

Binary atomic silicon logic

et al. 2018

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It has long been anticipated that the ultimate in miniature circuitry will be crafted of single atoms. Despite many advances made in scanned probe microscopy studies of molecules and atoms on surfaces, challenges with patterning and limited thermal stability have remained.Here we make progress toward those challenges and demonstrate rudimentary circuit elements through the patterning of dangling bonds on a hydrogen-terminated silicon surface. Dangling bonds sequester electrons both spatially and energetically in the bulk band gap, circumventing short-circuiting by the substrate. We deploy paired dangling bonds occupied by one moveable electron to form a binary electronic building block.Inspired by earlier quantum dot-based approaches, binary information is encoded in the electron position allowing demonstration of a "binary wire" and an OR gate.The prospect of atom scale computing was initially indicated by "molecular cascades"where sequentially toppling molecules were arranged in precise configurations to achieve binary logic functions 1 . Many notable approaches toward molecular electronics 2-7 , atomic electronics 8,9 , and quantum-dot-based electronics 10-15 have also been explored.The quantum dot based approaches [16][17][18][19][20] are particularly attractive, as they provide a low power yet fast basis 21 to go beyond today's CMOS technology 22 . These approaches, however, require cryogenic temperatures to minimize the population of thermally-excited states and achieve the desired functionality. Variability among quantum dots and sensitivity to uncontrolled fields are

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confidence: 78%

Binary atomic silicon logic

et al. 2018

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“…The single dangling bond DBs on the otherwise hydrogen terminated Silicon (H-Si) (100)-2 × 1 surface have been shown to behave as quantum dots capable of holding 0, 1, or 2 electrons (rendering the DB in a positive, neutral, or negative charge state). 45,46,55,56 The native charge state of a single DB can be modified by either varying the crystal doping level or the electrostatic environment surrounding the DB. 6,17 Using a degenerately n-doped crystal (see Methods), we perform Δf (V) spectroscopies which reveal the distinct charge transitions of the DB through discrete shifts in Δf associated with changes in the interaction between the tip apex atom and the DB, as well as a shift in the local contact potential difference.…”

Section: Resultsmentioning

confidence: 99%

“…6,17 Using a degenerately n-doped crystal (see Methods), we perform Δf (V) spectroscopies which reveal the distinct charge transitions of the DB through discrete shifts in Δf associated with changes in the interaction between the tip apex atom and the DB, as well as a shift in the local contact potential difference. 6,15,16,18,57 The transition bias between the neutral and negative ((0) to (−)) and the positive and neutral ((+) to (0)) charge states are routinely observed 0.2-0.4 V below the Fermi-level 6,17,18 and at the onset of the valence band, 46,58 respectively. Due to the location of the (+) to (0) charge transition, high tunneling current appears when probing Δf in the expected bias range, making it challenging to maintain tip integrity and distinguish the DB charging from higher bulk current contributions.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the anisotropy of the (2 × 1) reconstruction, [45][46][47][48] these DB structures are either patterned along a single dimer (in the [011] direction), creating what is commonly referred to as a bare dimer, 33,34,49,50 or along the same side of a dimer row (in the [011] direction) creating a DB wire. 35,37 DBs within a bare dimer are separated only by the shared dimer bond that forms a pi bond, 26,[51][52][53] while DBs within a DB wire are separated by a second layer back bonded Si atom.…”

Section: Introductionmentioning

confidence: 99%

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Ionic charge distributions in silicon atomic surface wires

et al. 2021

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“…This has been pursued by Koller et al [34] using a Yukawa screened hybrid functional, and by Skone et al [35], Ferrari et al [36], and Gerosa et al [37] in the form of global hybrid functionals. The resulting dielectric-dependent hybrid (DDH) functionals, primarily the global ones where α = ε −1 ∞ , have since been used to describe defects [38][39][40][41][42], band alignments of semiconductors [17], and electronic structures of aqueous solutions [43,44].…”

Section: Introductionmentioning

confidence: 99%

Nonempirical dielectric-dependent hybrid functional with range separation for semiconductors and insulators

Chen

Miceli

Rignanese

et al. 2018

Phys. Rev. Materials

148

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We present a general scheme of range-separated hybrid functionals in which the mixing parameters of Fock exchange are fully nonempirical and determined solely from the dielectric function.We showthat the full dielectric dependence leads to an unscreened Fock exchange in the short range, while in the long range the Fock exchange is correctly screened by the macroscopic dielectric constant. The range separation is obtained by fitting to the calculated static dielectric function in the long-wavelength limit. The resulting hybrid functional accurately accounts for electronic and structural properties of various semiconductors and insulators spanning a wide range of band gaps. We present a general scheme of range-separated hybrid functionals in which the mixing parameters of Fock exchange are fully nonempirical and determined solely from the dielectric function. We show that the full dielectric dependence leads to an unscreened Fock exchange in the short range, while in the long range the Fock exchange is correctly screened by the macroscopic dielectric constant. The range separation is obtained by fitting to the calculated static dielectric function in the long-wavelength limit. The resulting hybrid functional accurately accounts for electronic and structural properties of various semiconductors and insulators spanning a wide range of band gaps.

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Optimizing surface defects for atomic-scale electronics: Si dangling bonds

Cited by 19 publications

References 74 publications

Binary atomic silicon logic

Binary atomic silicon logic

Ionic charge distributions in silicon atomic surface wires

Nonempirical dielectric-dependent hybrid functional with range separation for semiconductors and insulators

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