Poster
3

Unconventional Thermal Magnon Hall Effect in a Ferromagnetic Topological Insulator

Avatar
Pierre A. Pantaleón Peralta
Mesoscale and Nanoscale Physics
Voices Powered byElevenlabs logo

Avatar
user

What is the main idea of the paper?

AI: The main idea of the paper is to investigate the thermal Hall effect of magnons in different materials, including chiral ferromagnets with weak Dzyaloshinskii-Moriya interaction, KOC modulated honeycomb ferromagnetic lattices with DMI and ${\mathrm{CrI}_3}$ monolayers, in order to understand their topological properties and the effect of various parameters on the thermal Hall conductivity. The authors explore the different topological phases that can be realized in these systems and the mechanism behind the sign changes in the thermal Hall conductivity seen in some of these phases. The paper concludes that these materials may be useful for the future design of two-dimensional thermal components since the thermal Hall conductivity can be easily tuned with external parameters such as the magnetic field and temperature.
Avatar
user

How is thermal conductivity defined?

AI: Thermal conductivity is not defined in this part of the paper, except for a discussion of thermal Hall conductivity in a magnonic system.

Authors

Christian Moulsdale, Pierre A. Pantaleón, Ramon Carrillo-Bastos, Yang Xian

Abstract

We present theoretically the thermal Hall effect of magnons in a ferromagnetic lattice with a Kekulé-O coupling (KOC) modulation and a Dzyaloshinskii-Moriya interaction (DMI). Through a strain-based mechanism for inducing the KOC modulation, we identify four topological phases in terms of the KOC parameter and DMI strength. We calculate the thermal magnon Hall conductivity ${\kappa^{xy}}$ at low temperature in each of these phases. We predict an unconventional conductivity due to a non-zero Berry curvature emerging from band proximity effects in the topologically trivial phase. We find sign changes of ${\kappa^{xy}}$ as a function of the model parameters, associated with the local Berry curvature and occupation probability of the bulk bands. Throughout, ${\kappa^{xy}}$ can be easily tuned with external parameters such as the magnetic field and temperature.

Follow Us on

2 comments

Avatar
scicastboard

Thank you for your submission.

Question from one of the expert in our Board. How do you define the thermal Hall effect in this system?
The usual linear response approach to, say,  electrical transport calculates current-current corellator and the corresponding Drude diagram, where the vertices are $e {\bf v}$. But with thermal transport - transport of energy its much trickier, because it's not clear how to define energy current especially in interacting systems. Do you face a similar challenge in this system? It's not entirely obvious where Eqs. (15) & (16) come from.
Thanks,
ScienceCast Board 

Avatar
pantagorico

Thanks for the question. The heat currents are due to a temperature gradient. Because it is a statistical force, a nice trick is to introduce a fictitious gravitational field. On the other hand, you are right that Eqs. 15 and 16 are not obvious. A beautiful explanation that deserves to be read can be found in arXiv:1103.1221v3
 

Answer
Add comment
Recommended SciCasts
Graph Self-Contrast Representation Learning
Avatar
Minjie Chen8 views
Graph Self-Contrast Representation Learning
Search for shortest paths based on the projective description of unweighted graphs
Avatar
melv78 views
Search for shortest paths based on the projective description of unweighted graphs
Spectral statistics of a minimal quantum glass model
Avatar
ScienceCast Board 76 views
Spectral statistics of a minimal quantum glass model
Variational Information Pursuit with Large Language and Multimodal Models for Interpretable Predictions
Avatar
Kwan Ho Ryan Chan26 views
Variational Information Pursuit with Large Language and Multimodal Models for Interpretable Predictions
A Bayesian Active Learning Approach to Comparative Judgement
Avatar
Andy Gray19 views
A Bayesian Active Learning Approach to Comparative Judgement
Cyclophobic Reinforcement Learning
Avatar
Stefan Wagner23 views
Cyclophobic Reinforcement Learning
Can Self-Supervised Neural Networks Pre-Trained on Human Speech distinguish Animal Callers?
Avatar
Eklavya Sarkar130 views
Can Self-Supervised Neural Networks Pre-Trained on Human Speech distinguish Animal Callers?
AI4Food-NutritionFW: A Novel Framework for the Automatic Synthesis and Analysis of Eating Behaviours
Avatar
Sergio Romero-Tapiador12 views
AI4Food-NutritionFW: A Novel Framework for the Automatic Synthesis and Analysis of Eating Behaviours
Self-Supervised Representation Learning with Cross-Context Learning between Global and Hypercolumn Features
Avatar
Zheng Gao25 views
Self-Supervised Representation Learning with Cross-Context Learning between Global and Hypercolumn Features
CLIPTrans: Transferring Visual Knowledge with Pre-trained Models for Multimodal Machine Translation
Avatar
Devaansh Gupta12 views
CLIPTrans: Transferring Visual Knowledge with Pre-trained Models for Multimodal Machine Translation
Generating the Ground Truth: Synthetic Data for Label Noise Research
Avatar
Sjoerd de Vries4 views
Generating the Ground Truth: Synthetic Data for Label Noise Research
Differentiable Frank-Wolfe Optimization Layer
Avatar
Zixuan Liu33 views
Differentiable Frank-Wolfe Optimization Layer
The Challenges of Machine Learning for Trust and Safety: A Case Study on Misinformation Detection
Avatar
Madelyne Xiao19 views
The Challenges of Machine Learning for Trust and Safety: A Case Study on Misinformation Detection
Where Would I Go Next? Large Language Models as Human Mobility Predictors
Avatar
Xinglei Wang17 views
Where Would I Go Next? Large Language Models as Human Mobility Predictors
A Generalization of Continuous Relaxation in Structured Pruning
Avatar
Brad Larson16 views
A Generalization of Continuous Relaxation in Structured Pruning
Flux Calibration of CHIME/FRB Intensity Data
Avatar
wael-alert149 views
Flux Calibration of CHIME/FRB Intensity Data
Job Shop Scheduling Benchmark: Environments and Instances for Learning and Non-learning Methods
Avatar
Robbert Reijnen20 views
Job Shop Scheduling Benchmark: Environments and Instances for Learning and Non-learning Methods
Emergent representations in networks trained with the Forward-Forward algorithm
Avatar
Emanuele Ballarin22 views
Emergent representations in networks trained with the Forward-Forward algorithm
Spear and Shield: Adversarial Attacks and Defense Methods for Model-Based Link Prediction on Continuous-Time Dynamic Graphs
Avatar
Dongjin Lee25 views
Spear and Shield: Adversarial Attacks and Defense Methods for Model-Based Link Prediction on Continuous-Time Dynamic Graphs
Area-norm COBRA on Conditional Survival Prediction
Avatar
Rahul Goswami29 views
Area-norm COBRA on Conditional Survival Prediction