Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Layered Metals as Polarized Transparent Conductors   The quest to improve transparent conductors balances two key goals:
increasing electrical conductivity and increasing optical transparency. To
improve both simultaneously is hindered by the physical limitation that good
metals with high electrical conductivity have large carrier densities that push
the plasma edge into the ultra-violet range. Transparent conductors are
compromises between electrical conductivity, requiring mobile electrons, and
optical transparency based on immobile charges to avoid screening of visible
light. Technological solutions reflect this trade-off, achieving the desired
transparencies by reducing the conductor thickness or carrier density at the
expense of a lower conductance. Here we demonstrate that highly anisotropic
crystalline conductors offer an alternative solution, avoiding this compromise
by separating the directions of conduction and transmission. Materials with a
quasi-two-dimensional electronic structure have a plasma edge well below the
range of visible light while maintaining excellent in-plane conductivity. We
demonstrate that slabs of the layered oxides Sr$_2$RuO$_4$ and
Tl$_2$Ba$_2$CuO$_{6+\delta}$ are optically transparent even at macroscopic
thicknesses >2$\mu$m for c-axis polarized light. Underlying this observation is
the fabrication of out-of-plane slabs by focused ion beam milling. This work
provides a glimpse into future technologies, such as highly polarized and
addressable optical screens, that advancements in a-axis thin film growth will
enable.

8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
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The categories of this paper are: q-fin