Seminarium Oddziału Badań Magnetyków
sala nr 6 (bud. II)
GdPtSb a possible candidate for Weyl Physics
mgr Abhinav Agarwal
Oddział Badań Magnetyków, INTiBS PAN
In the last 20 years, topology has attracted the attention of many physicists and material scientists. It’s an old concept deeply rooted in mathematics and geometry, but now we can see its direct manifestation in condensed matter systems. The discovery of the quantum Hall effect opened the opportunity to discuss topological phases. Different types of topological materials can be discussed, such as topological insulators, which are bulk gap material s consisting of zero gap surface states; in other words, the material is insulating in the bulk but has a zero band gap on the surface (3D) or edge (2D). Unlike in a topological insulator, the band structure of a topological semimetal exhibits bulk gapless points in the Brillouin zone (BZ) that have a nontrivial band structure and give rise to Weyl and Dirac fermions. Now, thousands of materials with nontrivial topological band structures have been reported. Half Heusler alloys with a very simple cubic crys tal structure provide a nice playground to study topological physics.
Recently, we have grown single crystals of GdPtSb, a half Heusler alloy and a possible candidate for Weyl Physics. I will present the results of our magnetic and transport measurements. GdPtSb is an
antiferromagnet with a transition temperature of 8K. At l ower temperatures (2K), it exhibits metamagnetic transitions. Room temperature measurement revealed its semimetallic nature with a superzone gap opening at the transition temperature. We also observed nonlinear Hall response, possibly a signature of Berry phase resulting from the nontrivial band structure. Interestingly, we observed negative magnetoresistance in parallel geometr y , which is a signature of chiral
