Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intrinsic persistent spin helix in two-dimensional group-IV
  monochalcogenide MX (M : Sn, Ge; X: S, Se, Te) monolayer   Energy-saving spintronics are believed to be implementable on the systems
hosting persistent spin helix (PSH) since they support an extraordinarily long
spin lifetime of carriers. However, achieving the PSH requires a unidirectional
spin configuration in the momentum space, which is practically non-trivial due
to the stringent conditions for fine-tuning the Rashba and Dresselhaus
spin-orbit couplings. Here, we predict that the PSH can be intrinsically
achieved on a two-dimensional (2D) group-IV monochalcogenide M X monolayer, a
new class of the noncentrosymmetric 2D materials having in-plane
ferroelctricity. Due to the C2v point group symmetry in the MX monolayer, a
unidirectional spin configuration is preserved in the out-of-plane direction
and thus maintains the PSH that is similar to the [110] Dresselhaus model in
the [110]-oriented quantum well. Our first-principle calculations on various MX
(M : Sn, Ge; X: S, Se, Te) monolayers confirmed that such typical spin
configuration is observed, in particular, at near the valence band maximum
where a sizable spin splitting and a substantially small wavelength of the spin
polarization are achieved. Importantly, we observe reversible out-of-plane spin
orientation under opposite in-plane ferroelectric polarization, indicating that
an electrically controllable PSH for spintronic applications is plausible.

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The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
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The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex