title: Bulk Fermi Surface of Charge-Neutral Excitations in SmB_{6} or Not: A Heat-Transport Study.
abstract: Recently, there have been increasingly hot debates on whether a bulk Fermi surface of charge-neutral excitations exists in the topological Kondo insulator SmB_{6}. To unambiguously resolve this issue, we perform the low-temperature thermal conductivity measurements of a high-quality SmB_{6} single crystal down to 0.1 K and up to 14.5 T. Our experiments show that the residual linear term of thermal conductivity at the zero field is zero, within the experimental accuracy. Furthermore, the thermal conductivity is insensitive to the magnetic field up to 14.5 T. These results demonstrate the absence of fermionic charge-neutral excitations in bulk SmB_{6}, such as scalar Majorana fermions or spinons and, thus, exclude the existence of a bulk Fermi surface suggested by a recent quantum oscillation study of SmB_{6}. This puts a strong constraint on the explanation of the quantum oscillations observed in SmB_{6}.
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China.
authors.forename: S
authors.initials: S
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China.
authors.forename: J K
authors.initials: JK
authors.lastname: Dong
authors.affiliation: Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China.
authors.forename: D
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: T
authors.initials: T
authors.lastname: Wu
authors.affiliation: Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: X H
authors.initials: XH
authors.lastname: Chen
authors.affiliation: Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Sun
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: S Y
authors.initials: SY
authors.lastname: Li