Spin-dependent optical properties of Ce-implanted MgAl<sub>2</sub>O<sub>4</sub>

ORAL

Abstract

Defect centers in diamond [1] and SiC [2,3] are common solid-state spin qubits with long coherence times T2 [4,5] with a variety of potential applications in quantum information sciences. Based on the guidelines for developing a new optically accessible qubit system [2,5], and theoretical predictions of qubit host materials with long T2 [6,7] we explore alternative qubit platforms. Here, we investigate the optical properties of Ce-implanted MgO and its mixed crystal with Al2O3.

We implant Ce into three substrates: bare MgO substrate without cap layer (Sample A), MgO with a 10-nm-thick Al2O3 layer (Sample B), and bare MgAl2O4 substrate (Sample C). The implantation energy and the dose are 100 keV and 1.0×1014 atoms/cm2, respectively. The substrates are annealed at 1000oC in Ar atmosphere for 2 hours.

The photoluminescence (PL) spectroscopy signal is measured using a spectrometer with an excitation wavelength of 325 nm. All samples show a broad peak at around 450 nm, consistent with the 4f-5d transition of the Ce3+ center. Sample C shows 14 (8) times larger intensity than Sample A (Sample B). This increase of the PL intensity suggests an increase in the formation of the luminescent Ce3+ center [8]. Next, we investigate the polarized optical properties of Ce-implanted MgAl2O4. The degree of circular polarization (DOCP) reaches ~2% under 500 mT at 4K. This behavior suggests spin-dependent PL [9,10], which is inevitable in optical initialization and readout of the spin qubit state.

*This work has been supported in part by Shimadzu Research Foundation; Takano Research Foundation; RIEC Cooperative Research Projects; JSPS Kakenhi Nos. 19KK010, 20H02178, and 23KK0092; and JST-PRESTO No. JPMJPR21B2.

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Publication: [1] P. Neumann et al., Science 320, 5881 (2008).
[2] J. R. Weber, W. F. Koehl, J. B. Varley et al., Proc. Natl. Acad. Sci. U.S.A. 107, 8513–8518 (2010).
[3] W. F. Kohel et al., Nature 479, 84 (2011).
[4] M. Atature et al., Nat. Rev. Mat. 3, 38–51 (2018).
[5] G. Wolfowicz, F. J. Heremans, C. P. Anderson et al., Nat. Rev. Mat. 6, 906 (2021).
[6] H. Seo et al., Nat. Rev. Commun. 7, 12395 (2016).
[7] S. Kanai et al., Proc. Natl. Acad. Sci. 119, e2121808119 (2022).
[8] J. Weimmerskirch-Aubatin et al., J. Alloys Compd. 622, 358 (2015).
[9] P. Liang et al., Phys. Rev. B 99, 024308 (2019).
[10] P. Siyushev et al., Nat Commun. 5, 3895 (2014).

Presenters

  • Manato Kawahara

    • Research Institute of Electrical Communication, Tohoku Univ.

Authors

  • Manato Kawahara

    • Research Institute of Electrical Communication, Tohoku Univ.

  • Yuichiro Abe

    • Tohoku Univ.

  • Koki Takano

    • Tohoku Univ.

  • F. Joseph F Heremans

    • Argonne National Laboratory
    • Argonne National Lab
    • Argonne
    • University of Chicago

  • Jun Ishihara

    • Tohoku Univ.

  • Sean E Sullivan

    • Argonne National Laboratory
    • memQ

  • Christian W Vorwerk

    • University of Chicago

  • Vrindaa Somjit

    • Argonne National Laboratory

  • Christopher P Anderson

    • The University of Chicago
    • University of Illinois Urbana-Champaign
    • Stanford University

  • Gary Wolfowicz

    • Argonne National Laboratory

  • Makoto Kohda

    • Tohoku Univ.

  • Shunsuke Fukami

    • Tohoku Univ

  • Giulia Galli

    • University of Chicago

  • David D Awschalom

    • University of Chicago

  • Hideo Ohno

    • Tohoku Univ

  • Shun Kanai

    • Tohoku University