We show a new method to differentiate conductivities from the surface states and the coexisting bulk states in topological insulators using a four-probe transport spectroscopy in a multiprobe scanning tunneling microscopy system. We derive a scaling relation of measured resistance with respect to varying interprobe spacing for two interconnected conduction channels to allow quantitative determination of conductivities from both channels. Using this method, we demonstrate the separation of 2D and 3D conduction in topological insulators by comparing the conductance scaling of Bi2Se3, Bi2Te2Se, and Sb-doped Bi2Se3 against a pure 2D conductance of graphene on SiC substrate. We also quantitatively show the effect of surface doping carriers on the 2D conductance enhancement in topological insulators. The method offers a means to understanding not just the topological insulators but also the 2D to 3D crossover of conductance in other complex systems.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.nanolett.5b04425 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Photonic axion insulator.
Science
January 2025
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
Axions, hypothetical elementary particles that remain undetectable in nature, can arise as quasiparticles in three-dimensional crystals known as axion insulators. Previous implementations of axion insulators have largely been limited to two-dimensional systems, leaving their topological properties in three dimensions unexplored in experiment. Here, we realize an axion insulator in a three-dimensional photonic crystal and probe its topological properties.
View Article and Find Full Text PDFPervasive RNA-binding protein enrichment on TAD boundaries regulates TAD organization.
Nucleic Acids Res
January 2025
Department of Orthopaedics and Traumatology, Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong SAR, China.
Mammalian genome is hierarchically organized by CTCF and cohesin through loop extrusion mechanism to facilitate the organization of topologically associating domains (TADs). Mounting evidence suggests additional factors/mechanisms exist to orchestrate TAD formation and maintenance. In this study, we investigate the potential role of RNA-binding proteins (RBPs) in TAD organization.
View Article and Find Full Text PDFConstructing the Dirac Electronic Behavior Database of Under-Stress Transition Metal Dichalcogenides for Broad Applications.
Adv Mater
January 2025
CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China.
Article Synopsis
- Discovering the optoelectronic properties of transition metal dichalcogenides (TMDCs) is crucial for next-gen electronic devices, with a focus on the impact of external strains on Dirac states, an area still being explored.
- A comprehensive database of 90 TMDC types was created, revealing that 27.3% exhibit Dirac materials with three distinct types of Dirac cones, influenced by external strain-induced electron localization.
- The study shows that TMDCs from tellurides with 1H phase enhance the formation of Dirac cones under stress, leading to metallic properties and increased charge transport, ultimately offering insights for the development of TMDCs in superconducting and optoelectronic applications.
A magneto-thermoelectric with a high figure of merit in topological insulator BiSb.
Nat Mater
January 2025
Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
High thermoelectric performance is generally achieved by synergistically optimizing two or even three of the contradictorily coupled thermoelectric parameters. Here we demonstrate magneto-thermoelectric correlation as a strategy to achieve simultaneous gain in an enhanced Seebeck coefficient and reduced thermal conductivity in topological materials. We report a large magneto-Seebeck effect and high magneto-thermoelectric figure of merit of 1.
View Article and Find Full Text PDFMass Acquisition of Dirac Fermions in Bi_{4}I_{4} by Spontaneous Symmetry Breaking.
Phys Rev Lett
December 2024
School of Physics, Beihang University, Haidian District, Beijing 100191, China.
Massive Dirac fermions, which are essential for realizing novel topological phenomena, are expected to be generated from massless Dirac fermions by breaking the related symmetry, such as time-reversal symmetry in topological insulators or crystal symmetry in topological crystalline insulators. Here, we report scanning tunneling microscopy and angle-resolved photoemission spectroscopy studies of α-Bi_{4}I_{4}, which reveals the realization of massive Dirac fermions in the (100) surface states without breaking the time-reversal symmetry. Combined with first-principles calculations, our experimental results indicate that the spontaneous symmetry breaking engenders two nondegenerate edge states at the opposite sides of monolayer Bi_{4}I_{4} after the structural phase transition, imparting mass to the Dirac fermions after taking the interlayer coupling into account.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!