Related Experiment Video
Updated: Apr 2, 2026
08:58
Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation
Published on: December 21, 2015
8.9K
Emerging conduction pathways in semiconducting bismuth-antimony alloys
Shriya Sinha1, Zecheng You2, Shane Smolenski2
1Applied Physics Program, University of Michigan, Ann Arbor, MI, United States of America.
Summary
Bismuth-antimony (Bi-Sb) alloys exhibit protected conduction pathways along defects. Researchers suppressed bulk conduction to reveal these topological features and measure a larger bandgap, showing promise for topological electronics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Topological Materials
Background:
- Bismuth-antimony (Bi-Sb) alloys are strong topological insulators.
- Topologically protected conduction pathways are predicted along extended defects in these alloys.
- Bulk conduction has previously obscured these topological features.
Purpose of the Study:
- To investigate carrier transport and electronic states in high-purity Bi1-xSbx single-crystals.
- To identify and characterize the residual conductivity associated with extended defects.
- To determine the bandgap and carrier mobility in Bi-Sb alloys.
Main Methods:
- Utilized high magnetic fields to suppress bulk conduction.
- Performed magnetotransport measurements and analyzed data using a two-band model.
- Employed angle-resolved photoemission spectroscopy (ARPES) to study electronic states.
Main Results:
- Successfully suppressed bulk conduction, revealing conductivity along extended defects.
- Determined a bandgap of at least 40 meV, exceeding previous estimates.
- Measured exceptionally high carrier mobility, up to 750,000 cm2V-1s-1.
Conclusions:
- Extended defects in Bi-Sb alloys host topologically protected conduction pathways.
- The identified bandgap and high mobility make Bi-Sb alloys highly suitable for topological electronics.
- This research clarifies the nature of conduction in these materials and their application potential.
Related Concept Videos
01:17Theory of Metallic Conduction
2.0K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
2.0K
01:27Biasing of Metal-Semiconductor Junctions
840
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
840
01:22Semiconductors
1.9K
There is variation in the electrical conductivity of materials - metals, semiconductors, and insulators that are showcased with the help of the energy band diagrams.
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
1.9K
01:24Metal-Semiconductor Junctions
1.4K
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
1.4K
02:35Band Theory
17.8K
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
17.8K
01:20Types of Semiconductors
1.8K
Intrinsic semiconductors are highly pure materials with no impurities. At absolute zero, these semiconductors behave as perfect insulators because all the valence electrons are bound, and the conduction band is empty, disallowing electrical conduction. The Fermi level is a concept used to describe the probability of occupancy of energy levels by electrons at thermal equilibrium. In intrinsic semiconductors, the Fermi level is positioned at the midpoint of the energy gap at absolute zero. When...
1.8K