Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate.
When an electronic system is subjected to a sufficiently strong magnetic field that the cyclotron energy is much larger than the Fermi energy, the system enters the extreme quantum limit (EQL) and becomes susceptible to a number of instabilities. Bringing a three-dimensional electronic system deeply into the EQL can be difficult however, since it requires a small Fermi energy, large magnetic field, and low disorder. Here we present an experimental study of the EQL in lightly-doped single crystals of strontium titanate. Our experiments probe deeply into the regime where theory has long predicted an interaction-driven charge density wave or Wigner crystal state. A number of interesting features arise in the transport in this regime, including a striking re-entrant nonlinearity in the current-voltage characteristics. We discuss these features in the context of possible correlated electron states, and present an alternative picture based on magnetic-field induced puddling of electrons.
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Anand
http://orcid.org/0000-0002-6839-6860
A
Bhattacharya
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.|Massachusetts Institute of Technology, 77 Mass Ave, Cambridge, Massachusetts 02139, USA.
Brian
B
Skinner
Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Guru
G
Khalsa
National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr, Tallahassee, Florida 32310, USA.
Alexey V
AV
Suslov
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