Related Experiment Video
Updated: Aug 19, 2025
13:56
Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
7.7K
Correlation-driven electronic nematicity in the Dirac semimetal BaNiS2
Christopher John Butler1, Yuhki Kohsaka1, Youichi Yamakawa2
1RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan.
Summary
Researchers found electronic nematicity, a form of electronic symmetry breaking, in BaNiS2. This correlated-electron behavior coexists with Dirac electrons, offering insights into novel quantum materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- BaNiS2 exhibits a Dirac nodal line band structure within a 2D Ni square lattice.
- Significant electronic correlation effects are anticipated in this system.
- Understanding these correlations is key to exploring novel quantum phenomena.
Purpose of the Study:
- To investigate correlated-electron behavior in BaNiS2.
- To identify the nature and origin of electronic nematicity in this material.
- To explore the coexistence of Dirac electrons and symmetry-breaking correlations.
Main Methods:
- Scanning tunneling microscopy (STM) was employed to probe the electronic properties.
- Quasiparticle interference (QPI) was observed to analyze electron scattering.
- Numerical modeling using a density wave (DW) equation framework was performed.
Main Results:
- Electronic nematicity was observed as C2-symmetry striped patterns in the local density of states.
- These patterns arise from a lifting of degeneracy among electron pockets at the Brillouin zone boundary.
- A momentum-dependent energy shift with a d-form factor was inferred, suggesting spin-fluctuation-driven nematicity.
Conclusions:
- BaNiS2 hosts a unique coexistence of Dirac electrons and symmetry-breaking electronic correlations.
- An unusual mechanism drives nematic instability, even with a low density of states at the Fermi energy.
- The Dirac points remain largely unaffected by the observed d-form factor.
More Related Videos
Related Concept Videos
01:24Metal-Semiconductor Junctions
431
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...
431
02:35Band Theory
15.4K
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,...
15.4K
02:42Valence Bond Theory
9.0K
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...
9.0K
01:20Types of Semiconductors
857
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...
857
01:01Energy Bands in Solids
1.1K
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
1.1K
01:27Biasing of Metal-Semiconductor Junctions
309
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...
309