Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of magnetic topological crystals   Topological phases of matter have established a new paradigm in physics,
bringing quantum phenomena to the macroscopic scale and hosting exotic emergent
quasiparticles. In this thesis, I theoretically and experimentally demonstrate
with my collaborators the first Weyl semimetal, TaAs, using angle-resolved
photoemission spectroscopy (ARPES), directly observing its emergent Weyl
fermions and topological Fermi arc surface states [Science 349, 6248 (2015);
Nat. Commun. 6, 7373 (2015); PRL 116, 066802 (2016)]. Next, I discover
high-degeneracy topological chiral fermions in the chiral crystals RhSi and
CoSi, with wide topological energy window, maximal separation in momentum space
and giant Fermi arcs [Nature 567, 500 (2019); Nat. Mat. 17, 978 (2018)]. I
establish a natural relationship between the structural and topological
chirality, associated with a robust topological state which we predict supports
a four-unit quantized photogalvanic effect [PRL 119, 206401 (2017)]. I also
discuss the first quantum topological superlattice, in multilayer
heterostructures consisting of alternating topological and trivial insulators
[Sci. Adv. 3, e1501692 (2017)]. The Dirac cones at each interface tunnel across
layers, forming an emergent atomic chain where the Dirac cones serve as atomic
orbitals. I achieve unprecedented control of hopping amplitudes within the
superlattice, realizing a topological phase transition. Lastly, I discover a
room-temperature topological magnet in Co$_2$MnGa [Science 365, 1278 (2019);
PRL 119, 156401 (2017)]. I observe topological Weyl lines and drumhead surface
states by ARPES, demonstrating a topological invariant supported by the
material's intrinsic magnetic order. I also find that the large anomalous Hall
effect in Co$_2$MnGa arises from the Weyl lines. I hope that my discovery of
Co$_2$MnGa establishes topological magnetism as a new frontier in condensed
matter physics.

18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga