Anisotropic Quantum Transport through a Single Spin Channel in the Magnetic Semiconductor EuTiO3

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Kazuki Maruhashi
  • Kei S. Takahashi
  • Sunao Shimizu
  • Ryosuke Kurihara
  • Atsushi Miyake
  • Masashi Tokunaga
  • Yoshinori Tokura
  • Masashi Kawasaki

Abstract

Magnetic semiconductors are a vital component in the understanding of quantum transport phenomena. To explore such delicate, yet fundamentally important, effects, it is crucial to maintain a high carrier mobility in the presence of magnetic moments. In practice, however, magnetization often diminishes the carrier mobility. Here, it is shown that EuTiO3 is a rare example of a magnetic semiconductor that can be desirably grown using the molecular beam epitaxy to possess a high carrier mobility exceeding 3000 cm2 V−1 s−1 at 2 K, while intrinsically hosting a large magnetization value, 7 μB per formula unit. This is demonstrated by measuring the Shubnikov–de Haas (SdH) oscillations in the ferromagnetic state of EuTiO3 films with various carrier densities. Using first-principles calculations, it is shown that the observed SdH oscillations originate genuinely from Ti 3d-t2g states which are fully spin-polarized due to their energetical proximity to the in-gap Eu 4f bands. Such an exchange coupling is further shown to have a profound effect on the effective mass and fermiology of the Ti 3d-t2g electrons, manifested by a directional anisotropy in the SdH oscillations. These findings suggest that EuTiO3 film is an ideal magnetic semiconductor, offering a fertile field to explore quantum phenomena suitable for spintronic applications.

Bibliographical metadata

Original languageEnglish
Article number1908315
Pages (from-to)1908315
Number of pages1
JournalAdvanced Materials
Volume32
Issue number24
Early online date8 May 2020
DOIs
Publication statusPublished - 1 Jun 2020