Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Novel Pauli-paramagnetic quantum phase in a Mott insulator   In Mott insulators, the strong electron-electron Coulomb repulsion prevents
metallicity and charge excitations are gapped. In dimensions greater than one,
their spins are usually ordered antiferromagnetically at low temperatures.
Geometrical frustrations can destroy this long-range order, leading to exotic
quantum spin liquid (QSL) states. However, their magnetic ground states have
been a long-standing mystery. Here we show that a QSL state in the organic Mott
insulator EtMe$_3$Sb[Pd(dmit)$_2$]$_2$ with two-dimensional triangular lattice
has Pauli-paramagnetic-like low-energy excitations, which are a hallmark of
itinerant fermions. Our torque magnetometry down to low temperatures (30 mK) up
to high fields (32 T) reveal distinct residual paramagnetic susceptibility
comparable to that in a half-filled two-dimensional metal. This demonstrates
that the system is in a magnetically gapless ground state, a critical state
with infinite magnetic correlation length. Moreover, our results are robust
against deuteration, pointing toward the emergence of an extended `quantum
critical phase', in which low-energy spin excitations behave as in paramagnetic
metals with Fermi surface, despite the frozen charge degree of freedom.

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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
18
The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
1
The categories of this paper are: cs
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The categories of this paper are: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn