by Mark T. Edmonds, James L

Slides:

Advertisements

Similar presentations

Spatial-temporal pattern of lower-crustal effective viscosities

Advertisements

Fig. 2 Characterization of fs-laser–induced degradation.

Fig. 3 Near-field maps of a multiply cracked α-(BEDT-TTF)2I3 crystal.

Fig. 2 Zeeman splitting of the plateau and associated Kondo feature.

Fig. 4 First-principles DFT calculations.

Probing ferroelectricity in a metal-gated WTe2 thin film sample

Fig. 3 Electron PSD in various regions.

Tuning of the conductance plateau of device 1 and quantum dot model

Fig. 6 Comparison of properties of water models.

Fig. 2 Ferroelectric domains resolved in WTe2 single crystals.

Fig. 3 Scan rate effects on the layer edge current.

Fig. 1 Schematics and design of the device structure.

Fig. 1 Study area and field site setting.

Fig. 1 Cryo-EM structure of yeast Elp123 showing its active site.

Fig. 2 Full-frame images recording the violation of a Bell inequality in four images. Full-frame images recording the violation of a Bell inequality in.

Fig. 2 Mineralization and surface colonization of films of three PBAT [poly(butylene adipate-co-terephthalate)] variants during a 6-week soil incubation.

Fig. 4 Energy balance analysis in STD systems.

Fig. 1 Phase diagram and FS topologies.

Fig. 3 Forward model. Forward model. Summary of the resampled Monte Carlo simulations shown as histograms for epoch 1 (red), epoch 2 (green), and epoch.

Emergence of resonances and prediction of distinct network responses

Fig. 3 Photon number statistics resulting from Fock state |l, S − l〉 interference. Photon number statistics resulting from Fock state |l, S − l〉 interference.

Fig. 2 2D QWs of different propagation lengths.

Fig. 1 A monolayer ReSe2 on a back-gated G/h-BN device.

Electronic structure of the oligomer (n = 8) at the UB3LYP/6-31G

Fig. 4 Resistance oscillations in Nc-G film.

Fig. 2 EUV TG signal. EUV TG signal. Black lines in (A), (B), and (C) are the EUV TG signals from Si3N4 membranes at LTG = 110, 85, and 28 nm, respectively,

Fig. 4 EUV TG signal from Si.

Fig. 6 WPS imaging of different chemical components in living cells.

Fig. 3 Correlation between magnetoresistance and emergence of superconductivity. Correlation between magnetoresistance and emergence of superconductivity.

Fig. 3 ET dynamics on the control and treatment watersheds during the pretreatment and treatment periods. ET dynamics on the control and treatment watersheds.

Fig. 2 Electronic structure of the Kagome area.

Fig. 2 Gate and magnetic field dependence of the edge conduction.

Fig. 4 Evolution of fraction of sickled RBCs under hypoxia.

Experimental phase diagram of zero-bias conductance peaks in superconductor/semiconductor nanowire devices by Jun Chen, Peng Yu, John Stenger, Moïra Hocevar,

Fig. 2 Results of the learning and testing phases.

by Masaki Yamawaki, Masato Ohnishi, Shenghong Ju, and Junichiro Shiomi

Fig. 4 SPICE simulation of stochasticity.

Fig. 2 Asymmetric MR of LMO within the ac plane.

by Thomas Zettl, Rebecca S

Fig. 2 Comparison of 1L, 2L, and 3L single crystals.

Fig. 4 Relationships between light and economic parameters.

Fig. 4 Reactive MD simulation showing the origins of chemical and physical effects on friction. Reactive MD simulation showing the origins of chemical.

Fig. 1 Experimental strategy and elemental and morphological analysis of 3D/2D perovskite bilayer. Experimental strategy and elemental and morphological.

Fig. 1 Location of the Jirzankal Cemetery.

Fig. 4 CO2 emission changes triggered by the JJJ clean air policy.

Fig. 5 Potential-energy energy profiles of 1-HAQ.

Structure of the laser-chemical tailored spongy Ni(TPA/TEG) catalyst

Fig. 2 Comparison of the observed DRs and the estimates by the VR model and FL. Comparison of the observed DRs and the estimates by the VR model and FL.

Fig. 4 The relationship between the total mean absolute momentum disturbance 〈∣p∣〉zB (in units of ℏ/D) and fringe visibility V. The relationship between.

Fig. 3 Depth-resolved structural characterization of perovskite nanocrystals in npSi films. Depth-resolved structural characterization of perovskite nanocrystals.

Fig. 1 Global distribution of data.

Fig. 2 Large-scale μXRF and EDS characterization of the text-containing side of the TS. Large-scale μXRF and EDS characterization of the text-containing.

Fig. 2 Characterization of metal-chalcogenide thin films.

Fig. 4 Spatial mapping of the distribution and intensity of industrial fishing catch. Spatial mapping of the distribution and intensity of industrial fishing.

Fig. 6 MD simulations of assembled binary supraballs.

Fig. 3 TEM evidence of carbon doping in WS2.

Fig. 1 Distribution of deformation and aqueous alteration in MIL

Fig. 3 Supraballs and films assembled from binary 219/217nm SPs/SMPs.

Fig. 2 Supraballs and films from binary SPs.

Fig. 2 Growth kinetics of borophene on silver.

The combined signal spectra of PSD for protons and helium nuclei

Fig. 4 Analysis of charge storage mechanism in ZnxCo1−xO NRs.

Fig. 1 STEM data: Original and processed by neural networks.

Fig. 3 Optimization of the antidot GNR structure.

Comparison of STM data on point impurities with DFT calculations

Fig. 4 Borophene-graphene vertical heterostructures.

Fig. 1 Atomic structure of U1−xThxSb2.

Fig. 2 Wavelength tuning with temperature.

Fig. 2 DFT calculations of stability and bandstructure of gallenene polymorphs. DFT calculations of stability and bandstructure of gallenene polymorphs.

Electronic states of U1−xThxSb2 and their temperature evolution

Presentation transcript:

Spatial charge inhomogeneity and defect states in topological Dirac semimetal thin films of Na3Bi by Mark T. Edmonds, James L. Collins, Jack Hellerstedt, Indra Yudhistira, Lídia C. Gomes, João N. B. Rodrigues, Shaffique Adam, and Michael S. Fuhrer Science Volume 3(12):eaao6661 December 22, 2017 Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Fig. 1 Large-area morphology and spectroscopy of 20-nm Na3Bi on Si(111). Large-area morphology and spectroscopy of 20-nm Na3Bi on Si(111). (A) Large-area (400 nm × 380 nm) topographic STM image (bias voltage V = −3 V and tunnel current I = 50 pA). Inset: Atomic-resolution STM image with a lattice constant of 5.45 Å (taken on a separate 20-nm Na3Bi film) showing an individual Na vacancy at the surface. (B) STM topography (V = 300 mV and I = 250 pA) on a 45 nm × 45 nm region of Na3Bi. (C) STM topography (V = −550 mV and I = 200 pA) on a 30 nm × 30 nm region of Na3Bi. (D) STM topography (V = −50 mV and I = 100 pA) on a 30 nm × 30 nm region of Na3Bi on sapphire [α-Al2O3(0001)]. (E) Area-averaged scanning tunneling spectra (vertically offset for clarity) corresponding to four different regions of the sample. Black spectra corresponding to the region in (B) and red spectra (topography not shown) were taken immediately after growth, whereas the blue spectra corresponding to the region in (C) and green spectra (topography not shown) were taken 1 week after growth. Feature ED reflects the Dirac point, which corresponds to the minimum in the LDOS, and D represents the resonance feature (discussed in the main text). Mark T. Edmonds et al. Sci Adv 2017;3:eaao6661 Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Fig. 2 Charge puddling profiles of p-type and n-type Na3Bi. Charge puddling profiles of p-type and n-type Na3Bi. (A) Dirac point energy map of the 45 nm × 45 nm (90 pixels × 90 pixels) region of p-type Na3Bi on Si(111) (V = −250 mV and I = 250 pA), corresponding to region A represented in Fig. 1B. Scale bar, 15 nm. (B) Dirac point energy map of the 30 nm × 30 nm (60 pixels × 60 pixels) region of n-type Na3Bi Si(111) corresponding to region B of Fig. 1C (V = −150 mV and I = 200 pA). Scale bar, 10 nm. (C) Dirac point energy map of the 30 nm × 30 nm (60 pixels × 60 pixels) region of n-type Na3Bi Si(111) grown on α-Al2O3(0001) (labeled region C) (V = −150 mV and I = 200 pA). Scale bar, 10 nm. (D) Upper, middle, and lower panels representing histograms of the Dirac point energy maps in (A) to (C), respectively. The histograms are color-coded to reflect the intensity scale in the corresponding Dirac point energy map. (E) Plot of spatial coherence length as a function of Fermi energy, comparing the experimental data for region A (red triangle), region B (blue triangle), and region C (purple diamond) to theoretical predictions (shaded region) where the upper bound (solid line) is defined using vF = 2.4 × 105 ms−1 and α = 0.069, whereas the lower bound (dashed line) uses vF = 1.4 × 105 ms−1 and α = 0.174 (24). Mark T. Edmonds et al. Sci Adv 2017;3:eaao6661 Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Fig. 3 Determining the bound state defect resonance. Determining the bound state defect resonance. (A) Map of the dI/dV magnitude at the defect resonance energy, where defects are shown as red circles. (B) dI/dV point spectra (taken on region B) on/off the defect site, at locations corresponding to the defect site (black), then 1 nm (red), 3 nm (purple), 5 nm (green), and 7 nm (brown) away from the defect. (C) Crystal structure of Na3Bi, with the surface-terminated Na labeled Na(2) (gold), with the remaining Na atoms in blue with the Na bonded to Bi in the hexagonal lattice labeled Na(1) and the Bi atoms in gray. (D) Comparison between DFT calculations of the DOS for Na3Bi with an Na(2) vacancy at the surface of a 2 × 2 × 3 cell (red curve), an Na(2) vacancy inside a 2 × 2 × 2 cell (blue curve), and a bulk Na(2) vacancy (black curve) and the experimental STS curve for a 20-nm Na3Bi film (green curve). Energy scales of all spectra have been corrected so that 0 eV reflects the Dirac point. A vertical offset has been applied for clarity. (E) Accompanying electronic band structures for bulk Na3Bi with an Na(2) vacancy (left), an Na(2) vacancy inside a 2 × 2 × 2 cell (middle), and an Na(2) vacancy at the surface of a 2 × 2 × 3 cell (right). Mark T. Edmonds et al. Sci Adv 2017;3:eaao6661 Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Fig. 4 Tip-induced ionization rings around large defects. Tip-induced ionization rings around large defects. (A) STM topography (V = −250 mV and I = 250pA) on a 60 nm × 60 nm region of Na3Bi. Fixed-bias dI/dV maps taken at (B) −196 mV, (C) −216 mV, and (D) −236 mV over the same region as (A) showing a ring-like feature centered around a large vacancy site highlighted by the dashed circle in (A). Mark T. Edmonds et al. Sci Adv 2017;3:eaao6661 Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).