Related Experiment Video
Updated: Sep 29, 2025
09:00
Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
10.1K
Spin-triplet superconductivity from excitonic effect in doped insulators
1Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139.
Summary
We reveal a new mechanism for unconventional superconductivity in doped band insulators, explaining electron pairing and Bose-Einstein condensate-Bardeen-Cooper-Schrieffer crossover. This theory predicts spin-triplet pairing in materials like ZrNCl and WTe2.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Unconventional superconductivity in doped band insulators remains poorly understood.
- Existing theories struggle to explain observed phenomena like electron pairing at low densities.
- The role of Coulomb repulsion in driving superconductivity in these systems is a key question.
Purpose of the Study:
- To propose a novel mechanism for unconventional superconductivity in doped band insulators.
- To explain the emergence of electron pairing and the Bose-Einstein condensate-Bardeen-Cooper-Schrieffer crossover.
- To predict specific material systems exhibiting these superconducting properties.
Main Methods:
- Theoretical modeling of Coulomb repulsion effects in doped band insulators.
- Analysis of virtual interband and excitonic processes contributing to pairing interactions.
- Investigation of electron pairing and its density dependence.
Main Results:
- A mechanism for short-ranged pairing interaction driven by Coulomb repulsion is presented.
- Electron pairing is observed upon infinitesimal doping, leading to a Bose-Einstein condensate-Bardeen-Cooper-Schrieffer crossover at low densities.
- The theory successfully explains puzzling superconducting behaviors.
Conclusions:
- The proposed mechanism provides a unified understanding of unconventional superconductivity in doped band insulators.
- Spin-triplet pairing is predicted for electron-doped ZrNCl and WTe2.
- This work opens new avenues for designing and discovering novel superconductors.
Related Concept Videos
02:42Valence Bond Theory
9.8K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
9.8K
03:02Colors and Magnetism
12.4K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.4K
01:20Types of Semiconductors
976
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...
976
01:28Types Of Superconductors
1.2K
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
1.2K
01:03Atomic Nuclei: Nuclear Spin State Overview
1.2K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of...
1.2K
01:17Spin–Spin Coupling: One-Bond Coupling
1.1K
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
1.1K