Electronic properties of zigzag graphene nanoribbons on Si(001)

Zhang, Zhuhua; Guo, Wei

doi:10.1063/1.3179426

Cited by 28 publications

(28 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many strategies have been tried to realize band gap in graphene, such as cutting graphene into graphene nanoribbons (GNRs) with appropriate edge structure and width [16][17][18][19][20][21], substrateinduced gap opening method [14,[21][22][23][24][25] and tensional straining method [26,27]. Among those methods, opening band gap by straining is regarded as an economical and effective method in engineering practice, and there are indeed proved examples in carbon nanotube materials and Si nanowire based photonic devices [28,29].…”

Section: Introductionmentioning

confidence: 99%

Tunable band structures of polycrystalline graphene by external and mismatch strains

Shi

Wei

2012

Acta Mech Sin

View full text Add to dashboard Cite

Lacking a band gap largely limits the application of graphene in electronic devices. Previous study shows that grain boundaries (GBs) in polycrystalline graphene can dramatically alter the electrical properties of graphene. Here, we investigate the band structure of polycrystalline graphene tuned by externally imposed strains and intrinsic mismatch strains at the GB by density functional theory (DFT) calculations. We found that graphene with symmetrical GBs typically has zero band gap even with large uniaxial and biaxial strain. However, some particular asymmetrical GBs can open a band gap in graphene and their band structures can be substantially tuned by external strains. A maximum band gap about 0.19 eV was observed in matched-armchair GB (5, 5) | (3, 7) with a misorientation of θ = 13• when the applied uniaxial strain increases to 9%. Although mismatch strain is inevitable in asymmetrical GBs, it has a small influence on the band gap of polycrystalline graphene.

show abstract

Section: Introductionmentioning

confidence: 99%

Tunable band structures of polycrystalline graphene by external and mismatch strains

Shi

Wei

2012

Acta Mech Sin

View full text Add to dashboard Cite

show abstract

“…It is seen that the bottom layer plus the substrate is semiconducting for the case of Z 6 -GNR but metallic for the case of Z 7 -GNR, consistent with our previous study of single Z-GNRs on the substrate. 24 On the other hand, the top layer GNR shows a band gap of about 0.21 eV in the case of Z 6 -GNR and 0.23 eV in the case of Z 7 -GNR, lower than that of 0.33 eV of a freestanding single-layer Z 6 -and Z 7 -GNRs. In addition, a slight breaking of spin degeneracy is observed for both the top ribbon layers due to asymmetrical interaction of two edges with the bottom layer.…”

Section: A Structural and Electronic Properties For Bilayer Z-gnrs Omentioning

confidence: 99%

“…All the adsorption features are consistent with the case of single-layer Z-GNRs on the same substrate. 24 The top GNR layer is weakly bound to the underlying layer at an average interlayer distance around 3.38 Å, slightly larger than the bulk graphite value of 3.35 Å, and curved to the same shape as the bridgelike bottom layer for all the studied bilayer Z-GNRs. The weak coupling from the bottom layer is also supported by the total charge-density distribution in the adsorbed Z 7 -GNR bilayer system shown in Fig.…”

Section: A Structural and Electronic Properties For Bilayer Z-gnrs Omentioning

confidence: 99%

“…Stronger binding of the bottom layer with the substrate in the adsorbed bilayer Z 6 -GNR is crucial for the appearance of semiconducting properties in the whole system. 24 …”

Section: E Bias-induced Modulation In Electronic Properties Of the Amentioning

confidence: 99%

“…[21][22][23] In particular, when single-layer Z-GNRs are adsorbed on silicon sub-strates, they possess semiconducting or metallic character depending on the ribbon width. 24 So, how the ME effect in the adsorbed bilayer Z-GNR changes with ribbon width also deserves further study. ͑3͒ The magnetic properties are actually determined by the electronic structures of the host materials and the magnetic modulation actually implies the change in electronic properties.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tuning the magnetic and electronic properties of bilayer graphene nanoribbons on Si(001) by bias voltage

et al. 2010

Self Cite

View full text Add to dashboard Cite

We report on a systematic study of bias-voltage-induced modulation of magnetic and electronic properties of bilayer zigzag graphene nanoribbons ͑Z-GNRs͒ on Si͑001͒ substrate by first-principles calculations. We show that the intrinsically nonmagnetic bilayer Z-GNRs exhibit magnetic ordering on the top layer while the bottom layer serves as a nonmagnetic buffer layer when adsorbed on the substrate. Interestingly, the adsorbed bilayers display distinct ribbon-width-dependent magnetoelectric effect under bias voltages. The magnetoelectric coefficient oscillates with increasing ribbon width, which arises from an interesting interplay of the interaction of the bottom ribbon layer with the substrates and the decay length of the localized edge states in Z-GNRs. Moreover, our calculations reveal that the electronic band gap of the top ribbon layer also can be effectively modulated by the applied bias voltage, which can lead to a semiconductor-to-metal transition in the top magnetic semiconductor layer. These results provide insights into the intriguing behaviors of Z-GNRs on substrates and raise the prospects of developing an innovative path toward graphene-based electronic and spintronic devices by integrating the emerging nanoscale graphene systems with existing silicon technology.

show abstract

Distributed parallel compilation of MSBNs

Cercone

2009

Concurrency and Computation

View full text Add to dashboard Cite

Multiply sectioned Bayesian networks (MSBNs) support multiagent probabilistic inference in distributed large problem domains. Inference with MSBNs can be performed using their compiled representations. The compilation involves moralization and triangulation of a set of local graphical structures. Privacy of agents may prevent us from compiling MSBNs at a central location. In earlier work, agents performed compilation sequentially via a depth-first traversal of the hypertree that organizes local subnets, where communication failure between any two agents would crush the whole work. In this paper, we present an asynchronous compilation method by which multiple agents compile MSBNs in full parallel. Compared with the traversal compilation, the asynchronous one is robust, self-adaptive, and fault-tolerant. Experiments show that both methods provide similar quality compilation to simple MSBNs, but the asynchronous one provides much higher quality compilation to complex MSBNs. Empirical study also indicates that the asynchronous one is consistently faster than the traversal one. Proposition 6. If T f t is properly set, Requirements 1 and 2 would be satisfied by the compiled hypertree MSDAG when PCoCompilation halts.Proof. Similar to the proof to Proposition 4.With a similar analysis as for the parallel cooperative moralization process, we have Proposition 7 for PCoCompilation regarding the termination time. 1 and 2 satisfied. ‡ Similarly for the parallel moralization, the input needs to be consistent hypertree MSDAGs. Figure 10. Standard deviation of the amount of fill-ins produced from the parallel triangulation with or without moralization fill-ins distributed in advance. Proposition 7. Let T m be the maximum time two agents on the hypertree need to exchange a set of fill-ins properly with each other. Let T c be the maximum time an agent needs to finish a while loop cycle. Then if T f t ≥ T m , and no fill-in is observed within T f t + (0 ≤ ≤ T c ), PCoCompilation would halt safely with RequirementsFigure 11. Triangulation time by the traversal and the parallel compilations on MSBNs b − j.of triangulation, and in particular, at the end of each pass of triangulation, extra examination is needed to determine the completion of triangulation and such examination has similar computational complexity as one pass triangulation, whereas the parallel method examines the completion of triangulation in triangulating.

show abstract

Electronic properties of zigzag graphene nanoribbons on Si(001)

Cited by 28 publications

References 24 publications

Tunable band structures of polycrystalline graphene by external and mismatch strains

Tunable band structures of polycrystalline graphene by external and mismatch strains

Tuning the magnetic and electronic properties of bilayer graphene nanoribbons on Si(001) by bias voltage

Distributed parallel compilation of MSBNs

Contact Info

Product

Resources

About