Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simple model for second-order topological insulators and loop-nodal
  semimetals in Transition Metal Dichalcogenides XTe$_2$ (X=Mo,W)   Transition metal dichalcogenides XTe$_{2}$ (X=Mo,W) have been shown to be
second-order topological insulators based on first-principles calculations,
while topological hinge states have been shown to emerge based on the
associated tight-binding model. The model is equivalent to the one constructed
from a loop-nodal semimetal by adding mass terms and spin-orbit interactions.
We propose to study a chiral-symmetric model obtained from the original
Hamiltonian by simplifying it but keeping almost identical band structures and
topological hinge states. A merit is that we are able to derive various
analytic formulas because of chiral symmetry, which enables us to reveal basic
topological properties of transition metal dichalcogenides. We find a linked
loop structure where a higher linking number (even 8) is realized. We construct
second-order topological semimetals and two-dimensional second-order
topological insulators based on this model. It is interesting that topological
phase transitions occur without gap closing between a topological insulator, a
topological crystalline insulator and a second-order topological insulator. We
propose to characterize them by symmetry detectors discriminating whether the
symmetry is preserved or not. They differentiate topological phases although
the symmetry indicators yield identical values to them. We also show that
topological hinge states are controllable by the direction of magnetization.
When the magnetization points the $z$ direction, the hinges states shift, while
they are gapped when it points the in-plane direction. Accordingly, the
quantized conductance is switched by controlling the magnetization direction.
Our results will be a basis of future topological devices based on transition
metal dichalcogenides.

15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
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The categories of this paper are: stat
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: eess