Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of topological states in two-dimensional Dirac systems by the
  dynamic spin susceptibility   We discuss dynamic spin susceptibility (DSS) in two-dimensional (2D) Dirac
electrons with spin-orbit interactions to characterize topological insulators.
The imaginary part of the DSS appears as an absorption rate in response to a
transverse ac magnetic field, just as in an electron spin resonance experiment
for localized spin systems. We found that when the system is in a static
magnetic field, the topological state can be identified by an anomalous
resonant peak of the imaginary part of the DSS as a function of the frequency
of the transverse magnetic field $\omega$. In the absence of a static magnetic
field, the imaginary part of the DSS becomes a continuous function of $\omega$
with a threshold frequency $\omega_{\rm c}$. In this case, the topological and
the trivial phases can also be distinguished by the values of $\omega_{\rm c}$
and by the line shapes. Thus the DSS is an experimentally observable physical
quantity to characterize a topological insulator directly from bulk properties,
without observing a topological transition.

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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
2
The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas