Related Experiment Video
Updated: Jul 10, 2025
07:19
Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy
Published on: September 15, 2016
10.4K
Berry Curvature Spectroscopy from Bloch Oscillations
Christophe De Beule1,2, E J Mele1
1Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Physical Review Letters
|November 24, 2023
Summary
Artificial crystals with large periodicities exhibit Bloch oscillations under electric fields. Their optical response resonates at terahertz frequencies, linked to Berry curvature components.
Area of Science:
- Condensed matter physics
- Solid-state physics
- Materials science
Background:
- Artificial crystals like moiré superlattices offer tunable electronic properties.
- Bloch oscillations are quantum mechanical phenomena occurring in periodic potentials under electric fields.
- Terahertz (THz) frequencies are relevant for advanced spectroscopy and electronics.
Purpose of the Study:
- To investigate the optical response of artificial crystals subjected to static electric fields.
- To explore the connection between Bloch oscillations and resonant optical phenomena.
- To theoretically model the THz optical response and its relation to material properties.
Main Methods:
- Utilizing a semiclassical band-projected theory.
- Analyzing the optical response of moiré superlattices under static electric fields.
- Calculating dressed Hall conductivity and its dependence on Berry curvature.
Main Results:
- Optical response shows resonances at Bloch oscillation frequencies in the THz regime.
- Resonances in dressed Hall conductivity are directly proportional to lattice Fourier components of Berry curvature.
- Demonstrated with a low-energy model on an effective honeycomb lattice.
Conclusions:
- Static electric fields can induce THz-frequency resonances in artificial crystals.
- Berry curvature's Fourier components are key determinants of these THz optical resonances.
- This work provides a theoretical framework for designing materials with tailored THz responses.
Related Concept Videos
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
1.3K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
1.3K
01:24IR Spectroscopy: Molecular Vibration Overview
2.4K
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...
2.4K
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
01:20Raman Spectroscopy: Overview
415
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...
415
01:16Spectrophotometry: Introduction
3.2K
Spectrophotometry is the quantitative measurement of the absorption, reflection, diffraction, or transmission of electromagnetic radiation through a material as a function of the intensity and wavelength of the radiation. A spectrophotometer is a device used to measure the change in the radiation intensity caused by its interaction with the material.
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
3.2K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.0K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.0K