Highly mobile gapless excitations in a two-dimensional candidate quantum spin liquid.
The nature of quantum spin liquids, a novel state of matter where strong quantum fluctuations destroy the long-range magnetic order even at zero temperature, is a long-standing issue in physics. We measured the low-temperature thermal conductivity of the recently discovered quantum spin liquid candidate, the organic insulator EtMe3Sb[Pd(dmit)2]2. A sizable linear temperature dependence term is clearly resolved in the zero-temperature limit, indicating the presence of gapless excitations with an extremely long mean free path, analogous to excitations near the Fermi surface in pure metals. Its magnetic field dependence suggests a concomitant appearance of spin-gap-like excitations at low temperatures. These findings expose a highly unusual dichotomy that characterizes the low-energy physics of this quantum system.
Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. yamashitaminoru@scphys.kyoto-u.ac.jp
Minoru
M
Yamashita
Norihito
N
Nakata
Yoshinori
Y
Senshu
Masaki
M
Nagata
Hiroshi M
HM
Yamamoto
Reizo
R
Kato
Takasada
T
Shibauchi
Yuji
Y
Matsuda