Confined Doping on a Metallic Atomic Chain Structure

Barke, Ingo; Polei, Stefan; Oeynhausen, Viola von; Meiwes‐Broer, Karl‐Heinz

doi:10.1103/physrevlett.109.066801

Cited by 22 publications

(16 citation statements)

References 41 publications

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“…In contradiction with the present conclusion, the previous STM/S work interpreted the length-dependent energy shift of wire segments as the confined doping effect of adatoms [20]. This interpretation provides the length dependence of 1/L instead 1/L 2 .…”

contrasting

confidence: 99%

Electron Quantization in Broken Atomic Wires

Hwan¹,

Yeom²

2015

Phys. Rev. Lett.

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We demonstrate using scanning tunneling microscopy and spectroscopy the electron quantization within metallic Au atomic wires self-assembled on a Si(111) surface and segmented by adatom impurities. The local electronic states of wire segments with a length up to 10 nm are investigated as terminated by two neighboring Si adatoms. One dimensional (1D) quantum well states are well resolved by their spatial distributions and the inverse-length-square dependence in their energies. The quantization also results in the quantum oscillation of the conductance at the Fermi level. These results deny the dopant role of the adatoms assumed for a long time but indicate their strong scattering nature. The present approach provides a new and convenient platform to investigate 1D quantum phenomena with atomic precision.One-dimensional (1D) materials systems have been investigated extensively because both of the intriguing and exotic nature of their electrons and of the interest in nano or atomic scale devices. Characteristic 1D electronic properties of fundamental interest include the TomonagaLuttinger liquid [1,2], the charge-density wave [3,4], the unconventional superconductivity [5], and more recently, Majorana Fermions [6,7]. However, 1D materials systems are notorious in their intrinsic susceptibility to extrinsic perturbations such as defects and impurities [8][9][10]. In microscopic points of view, defects or impurities can have various different actions; local or global doping, local lattice distortions, weak or strong electron scatterings and so on. Nevertheless, the direct atomic scale investigation on those actions has been far from being sufficient.The self-assembled atomic wire structure of the Si(111)5×2-Au surface is an excellent candidate system for a systematic study on the interactions of impurities with atomic scale precision. This system has a wellordered Au-Si atomic wire array with a well-defined 1D metallic band [11]. Its atomic structure has been debated for a long time but very recently determined conclusively [12,13]. This surface is intrinsically endowed with Si adatom impurities ejected from the Si substrate [14,15], whose density can be controlled globally [11] or in the atom-by-atom fashion [16]. The electronic band structure is systematically tuned by the adatom density from a metal to a gapped insulator globally [11] or locally [17]. This controllability opens up an unprecedented possibility for a systematic study of impurity effects in an atomic scale 1D metallic system [18].For quite a long time, a Si adatom on this model 1D system was believed to act as a charged impurity [19] and a recent scanning tunneling microscopy and spectroscopy (STM/S) work claimed the observation of the local 'confined' doping effect of individual adatoms [20]. Within this picture, an impurity atom act only to locally shift the energy of the 1D metallic state while the electron scattering and the Friedel oscillation [21] by the impurity are totally neglected. In this work, we focus on the electron scattering by a Si a...

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contrasting

confidence: 99%

Electron Quantization in Broken Atomic Wires

Hwan¹,

Yeom²

2015

Phys. Rev. Lett.

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“…These Si adatoms, which are not shown in the structural models in Fig. 1, have been verified by several research groups [5,[14][15][16].…”

Section: Introductionsupporting

confidence: 57%

“…The fact that in the (yx) Raman spectra features arise which have no counterpart in the calculation would, by implication, result if structural domains distinct from the (5 × 2) structure discussed so far are sampled as well. This is indeed the case as Si adsorbate atoms have been found on the surface by several groups [5,15,16]. The Si adsorbate atoms were found to allocate in domains which coexist with the pure (5 × 2) structure which is used for the calculations here.…”

Section: First-principles Calculationsmentioning

confidence: 66%

Vibration eigenmodes of the Au- (5×2) /Si(111) surface studied by Raman spectroscopy and first-principles calculations

et al. 2016

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Ordered submonolayers of adsorbate atoms on semiconductor surfaces constitute a playground for electronic correlation effects, which are tightly connected to the local atomic arrangement and the corresponding vibration eigenmodes. We report on a study of the vibration eigenmodes of Au-covered Si(111) surfaces with (5 × 2) reconstruction using polarized Raman spectroscopy and first-principles calculations. Upon Au coverage, the vibration eigenmodes of the clean reconstructed Si(111)-(7 × 7) surface are quenched and replaced by new eigenmodes, determined by the Au-(5 × 2) reconstruction. Several polarization-dependent surface eigenmodes emerge in the spectral range from 25 to 120 cm −1 , with the strongest ones at 29, 51, and 106 cm −1. In our first-principles calculations we have determined the vibration frequencies, the corresponding elongation patterns, and the Raman intensities for two different structure models currently discussed in the literature. The best agreement with the experimental results is achieved for a model with 0.7 monolayer coverage and seven Au atoms per unit cell, proposed by S. G. Kwon and M. H. Kang [Phys. Rev. Lett. 113, 086101 (2014)].

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“…Moreover, on the Si(111)-Au (5 × 2) Si adatoms are intrinsically present and even mandatory for the formation of the geometry with the lowest (free) energy [16,17]. The control of their density during preparation allows even tuning of the 1D band structure [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Tuning the conductivity along atomic chains by selective chemisorption

et al. 2017

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Adsorption of Au on vicinal Si(111) surfaces results in growth of long-range ordered metallic quantum wires. In this paper, we utilized site-specific and selective adsorption of oxygen to modify chemically the transport via different channels in the systems Si(553)-Au and Si(557)-Au. They were analyzed by electron diffraction and four-tip STM-based transport experiments. Modeling of the adsorption process by density functional theory shows that the adatoms and rest atoms on Si(557)-Au provide energetically favored adsorption sites, which predominantly alter the transport along the wire direction. Since this structural motif is missing on Si(553)-Au, the transport channels remain almost unaffected by oxidation.

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Confined Doping on a Metallic Atomic Chain Structure

Cited by 22 publications

References 41 publications

Electron Quantization in Broken Atomic Wires

Electron Quantization in Broken Atomic Wires

Vibration eigenmodes of the Au- (5×2) /Si(111) surface studied by Raman spectroscopy and first-principles calculations

Tuning the conductivity along atomic chains by selective chemisorption

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