April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)
Symposium Supporters
2024 MRS Spring Meeting
QT05/QT07.04

Spiral Magnetism in a Weyl Semimetal

When and Where

May 8, 2024
4:30pm - 5:00pm
QT05-virtual

Presenter(s)

Co-Author(s)

Fazel Fallah Tafti1,Xiaohan Yao1,Jonathan Gaudet2,Predrag Nikolic3

Boston College1,National Institute of Standards and Technology2,George Mason University3

Abstract

Fazel Fallah Tafti1,Xiaohan Yao1,Jonathan Gaudet2,Predrag Nikolic3

Boston College1,National Institute of Standards and Technology2,George Mason University3
We present evidence of spiral magnetic ordering in the Weyl semimetal SmAlSi from transport and neutron diffraction experiments. This material is a member of RAlSi family where R is the rare-earth. We show that a large magnetocrystalline anisotropy in PrAlSi, CeAlSi, and NdAlSi prevents the spiral order although chiral interactions may be present. However, SmAlSi shows a nearly isotropic crystal electric field which leads to its spiral order. We map the phase diagram of this material and reveal an A-phase at finite field and temperature. Within this phase, we observe a sizable topological Hall effect. We also find that the magnetic k-vector observed in SmAlSi matches the nesting between its Weyl nodes on the Fermi surface. As such, SmAlSi seems to be the first topological semimetal where spiral order is established from the direct engagement of Weyl electrons in magnetic interactions.

Keywords

chemical substitution | neutron scattering

Symposium Organizers

Jessica Boland, University of Manchester
Shelly Michele Conroy, Imperial College London
Ismail El Baggari, Harvard University
Juan Carlos Idrobo, University of Washington

Session Chairs

Shelly Michele Conroy
Rafal Kurleto
Stephan Lany

In this Session