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Title: Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate

Abstract

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. As a result, 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.

Authors:
ORCiD logo [1];  [2];  [3];  [4]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  3. National Institute of Standards and Technology, Gaithersburg, MD (United States); Cornell Univ., Ithaca, NY (United States)
  4. National High Magnetic Field Lab., Tallahassee, FL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Materials Sciences and Engineering Division
OSTI Identifier:
1333158
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; electronic properties and materials; phase transitions and critical phenomena

Citation Formats

Bhattacharya, Anand, Skinner, Brian, Khalsa, Guru, and Suslov, Alexey V. Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate. United States: N. p., 2016. Web. doi:10.1038/ncomms12974.
Bhattacharya, Anand, Skinner, Brian, Khalsa, Guru, & Suslov, Alexey V. Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate. United States. doi:10.1038/ncomms12974.
Bhattacharya, Anand, Skinner, Brian, Khalsa, Guru, and Suslov, Alexey V. 2016. "Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate". United States. doi:10.1038/ncomms12974. https://www.osti.gov/servlets/purl/1333158.
@article{osti_1333158,
title = {Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate},
author = {Bhattacharya, Anand and Skinner, Brian and Khalsa, Guru and Suslov, Alexey V.},
abstractNote = {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. As a result, 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.},
doi = {10.1038/ncomms12974},
journal = {Nature Communications},
number = ,
volume = 7,
place = {United States},
year = 2016,
month = 9
}

Journal Article:
Free Publicly Available Full Text
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  • When an electronic system is subjected to a sufficiently strong magnetic field that the cyclotron energy is larger than the Fermi energy, the system enters the extreme quantum limit" (EQL) and becomes susceptible to a number of instabilities. Bringing an electronic system deeply into the EQL can be very 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 samples remain good bulk conductors down to very low temperatures and high magnetic fields. A number of interesting featuresmore » arise in the transport upon entering the EQL, including a striking nonlinearity in the current-voltage characteristics. We discuss these features in the context of possible correlated electron states, and present evidence for magnetic-field induced puddling of electrons.« less
  • A promising method to generate the attosecond extreme ultraviolet (XUV) sources has been theoretically investigated emerging from the two-dimensional Ar{sup +} cluster driven by the spatially inhomogeneous field. The results show that with the introduction of the Ar{sup +} cluster model, not only the harmonic cutoffs are enhanced, but also the harmonic yields are reinforced. Furthermore, by properly moderating the inhomogeneity as well as the laser parameters of the inhomogeneous field, the harmonic cutoff can be further extended. As a result, three almost linearly polarized XUV pulses with durations of 40 as, 42 as, and 45 as can be obtained.
  • Barium Strontium Titanate (Ba{sub 1-x}Sr{sub x}TiO{sub 3}) or BST was prepared by solid state reaction method. Raw materials are BaCO{sub 3}, SrCO{sub 3}, and TiO{sub 2}. Those materials are mixed for 8 h, pressed, and sintered at temperature 1200°C for 2 h. Mole composition of Sr (x) was varied to study its influences on structural, morphological, and electrical properties of BST. Variation of (x) are x = 0; x = 0.1; and x = 0.5. XRD patterns showed a single phase of BST, which mean that mixture of raw materials was homogenous. Crystal structure was influenced by x. BaTiO{sub 3} and Ba{submore » 0.9}Ti{sub 0.1}TiO{sub 3} have tetragonal crystal structure, while Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} is cubic. The diffraction angle shifted to right side (angle larger) as the increases of x. Crystalline size of BaTiO{sub 3}, Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3}, and Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} are 38.13 nm; 38.62 nm; and 37.13 nm, respectively. SEM images showed that there are still of pores which were influenced by x. Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} has densest surface (pores are few and small in size). Sawyer Tower circuit showed that BaTiO{sub 3} and Ba{sub 0.9}Sr{sub 0.1} TiO{sub 3} is ferroelectric, while Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} is paraelectric. The dielectric constants of BaTiO{sub 3}, Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} and Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} at frequency of 1 KHz are 156; 196; and 83, respectively. Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} has relatively highest dielectric constant. It is considered that Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} has densest surface.« less