Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microscopic Origin of the Valley Hall Effect in Transition Metal
  Dichalcogenides Revealed by Wavelength Dependent Mapping   The band structure of many semiconducting monolayer transition metal
dichalcogenides (TMDs) possesses two degenerate valleys, with equal and
opposite Berry curvature. It has been predicted that, when illuminated with
circularly polarized light, interband transitions generate an unbalanced
non-equilibrium population of electrons and holes in these valleys, resulting
in a finite Hall voltage at zero magnetic field when a current flows through
the system. This is the so-called valley Hall effect that has recently been
observed experimentally. Here, we show that this effect is mediated by
photo-generated neutral excitons and charged trions, and not by inter-band
transitions generating independent electrons and holes. We further demonstrate
an experimental strategy, based on wavelength dependent spatial mapping of the
Hall voltage, which allows the exciton and trion contributions to the valley
Hall effect to be discriminated in the measurement. These results represent a
significant step forward in our understanding of the microscopic origin of
photo-induced valley Hall effect in semiconducting transition metal
dichalcogenides, and demonstrate experimentally that composite quasi-particles,
such as trions, can also possess a finite Berry curvature.

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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex