High magnetic fields and the correlation gap in SmB{sub 6}
- The Harrison M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States)
- National High Magnetic Field Laboratory, Pulsed Facility, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306 (United States)
- Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)
- Department of Physics, Tufts University, Medford, Massachusetts 02155 (United States)
We report the results of electrical resistivity measurements on SmB{sub 6} in magnetic fields as large as 18 T and pressures as large as 66 kbar. We find that the activation gap {Delta} extracted from these measurements has an anomalously weak field dependence, even when pressures of {similar_to}50 kbar are used to tune {Delta} to instability. Our results imply the existence of strong exchange interactions in the low-pressure, gapped state, and argue that {Delta} originates with many-body correlations. Nonetheless, the small, negative magnetoresistance {Delta}{rho}({ital H})/{rho}{sub {ital H}=0}{proportional_to}{minus}{ital H}{sup 2} observed below 50 kbar is completely accounted for by the weak field variation of {Delta}. A sign change in the magnetoresistance accompanies the gap collapse, with the high-pressure, gapless metal having {Delta}{rho}({ital H})/{rho}{sub {ital H}=0}{proportional_to}{ital H}{sup 3/2}. The Fermi surface deduced from these measurements is similar to that of noninteracting, trivalent LaB{sub 6}, but with a volume which increases rapidly with pressure.
- Research Organization:
- Ames National Laboratory
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 115855
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 10 Vol. 52; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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