Magnetic and Electronic Topological States in the Kagome-Net Magnet YMn₆Sn₆

Identification, understanding, and manipulation of novel electronic and magnetic states is essential for the discovery of new quantum materials for future spin-based electronic devices. In particular, materials that manifest an interplay of magnetism and electronic topology are subject to intense investigation; kagome net magnets are prime candidates. In this talk I will presnt the magnetotransport signatures of the magnetic and electronic topological states in the kagome net magnet YMn₆Sn₆.<br/>YMn₆Sn₆ crystallizes in the hexagonal space group P6/mmm with Mn atoms forming a kagome net in the basal plane. The material orders antiferromagnetically at 345 K and quickly transitions into an incommensurate spiral below 333 K. For a magnetic field applied in the <i>ab</i>-plane, a series of competing phases namely distorted spiral (DS), transverse conical spiral (TCS) and Fan-like (FL) phases are stabilized before polarizing to the forced ferromagnetic (FF) state. In this field orientation, this coumpoud shows an enigmatic topological Hall effect near room temperature within the TCS phase, which we attribute to a new fluctuation-driven mechanism. In addition to this THE, YMn₆Sn₆shows two other intuging magnetotransport features at lower temperatures: an anisotropic magnetoresistance drop due to a magnetization-driven topological phase transition (Lifshitz transition), and an interlayer MR due to the charge-spin coupling associated with the magnetic texture in the FL phase in absence of a strong spin orbit coupling. These phenomena provide a unique view into the magnetic and electronic topological states and their interplay in YMn₆Sn₆.