Related Experiment Video
Updated: Jun 29, 2025
07:44
Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems
Published on: April 28, 2016
15.1K
Resonant Raman scattering of few layers CrBr3
Łucja Kipczak1, Arka Karmakar2, Magdalena Grzeszczyk3
1Faculty of Physics, Institute of Experimental Physics, University of Warsaw, 02-093, Warsaw, Poland. lucja.kipczak@fuw.edu.pl.
Scientific Reports
|March 30, 2024
Summary
We studied chromium tribromide (CrBr3) thin layers using Raman scattering to understand their vibrational and magnetic properties. We observed distinct phonon modes and magnetic transitions, revealing insights into these 2D magnetic materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Magnetism
Background:
- Chromium tribromide (CrBr3) is a layered material exhibiting 2D magnetism.
- Understanding the interplay between vibrational and magnetic properties is crucial for spintronic applications.
Purpose of the Study:
- To investigate the vibrational and magnetic properties of CrBr3 thin layers.
- To explore the influence of excitation energy and thickness on Raman scattering.
- To identify phonon modes and their relation to magnetic phase transitions.
Main Methods:
- Raman scattering (RS) spectroscopy with varying laser excitation energies (1.96–3.06 eV).
- Polarization-resolved RS measurements.
- First-principles calculations.
- Temperature-dependent measurements on encapsulated CrBr3.
Main Results:
- Identified five phonon modes (A and E symmetries) in 12-layer CrBr3.
- Observed resonant enhancement of Raman scattering at 3.06 eV excitation, indicating interband electronic transitions.
- Detected alterations in phonon modes around the Curie temperature (Tc) for 16-layer CrBr3, signaling paramagnetic to ferromagnetic transition.
- Found minimal thickness dependence of phonon energies for layers thicker than 5 L.
Conclusions:
- Raman scattering is a sensitive probe for vibrational and magnetic properties of CrBr3.
- Resonant excitation conditions can be utilized to enhance Raman signals.
- Phonon mode behavior near Tc provides insight into magnetic ordering.
- Thickness effects are pronounced only in the thinnest CrBr3 layers.
Related Concept Videos
01:20Raman Spectroscopy: Overview
377
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
377
01:26Raman Spectroscopy Instrumentation: Overview
332
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
332
01:13¹H NMR: Complex Splitting
1.3K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.3K
01:24IR Spectroscopy: Molecular Vibration Overview
2.1K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
2.1K
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
1.0K
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single...
1.0K
01:13Attenuated Total Reflectance (ATR) Infrared Spectroscopy: Overview
361
Attenuated total reflectance (ATR) infrared spectroscopy is a powerful analytical technique used to study the composition of materials. It is widely employed in chemistry, materials science, forensic science, and other fields where sample characterization is required. ATR has several advantages over traditional transmission IR spectroscopy, including the requirement of little to no sample preparation and the ability to analyze a wide range of samples.
The ATR process begins by directing a beam...
The ATR process begins by directing a beam...
361