Related Experiment Video
Updated: May 15, 2026
10:36
Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials
Published on: January 21, 2016
Quantum anomalous Hall effect based on MnBi2Te4-family systems
Yang Chen1, Mohsin Rafique2, Jingjing Cao3
1State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
Summary
The quantum anomalous Hall effect (QAHE) is achieved in intrinsic magnetic topological insulators like MnBi2Te4 (MBT). This review details MBT
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Phenomena
Background:
- The quantum anomalous Hall effect (QAHE) offers dissipationless chiral edge transport without external magnetic fields.
- Early QAHE discoveries in doped topological insulators were limited by disorder and low temperatures (millikelvin regime).
- The intrinsic magnetic topological insulator MnBi2Te4 (MBT) provides a stoichiometric platform with ordered magnetic sublattices.
Purpose of the Study:
- To provide a comprehensive review of advancements in the MnBi2Te4 (MBT) family of materials.
- To connect experimental breakthroughs with theoretical predictions in intrinsic magnetic topological insulators.
- To explore new pathways for manipulating topological order and quantum phenomena.
Main Methods:
- Analysis of layer-dependent magnetic properties in MBT systems.
- Review of molecular beam epitaxy (MBE) growth and surface passivation techniques.
- Summary of theoretical and computational studies on advanced topological concepts.
Main Results:
- Demonstration of high-Chern-number states and precise quantization in MBT.
- Identification of intrinsic ferroelectricity and odd-parity magnetism in MBT.
- Prediction of light-induced quantum optical phenomena, including Floquet engineering.
Conclusions:
- The MBT family represents a significant advancement for realizing the QAHE at higher temperatures.
- Emerging theoretical predictions offer novel routes for controlling topological states.
- Future research directions include heterostructures and fractionalized topological states.
Related Concept Videos
02:42Valence Bond Theory
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...
01:30The Hall Effect
Edwin H. Hall, in the year 1879, devised an experiment that could be used to identify the polarity of the predominant charge carriers in a conducting material. From a historical perspective, this experiment was the first to demonstrate that the charge carriers in most metals are negative.
01:03Atomic Nuclei: Nuclear Spin State Overview
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 one, the...
03:02Colors and Magnetism
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 eye.
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 eye.
01:27π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
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 slanted or...
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 slanted or...