Abstract
Quantum light emitters capable of generating single photons with circular polarization and non-classical statistics could enable non-reciprocal single-photon devices and deterministic spin–photon interfaces for quantum networks. To date, the emission of such chiral quantum light relies on the application of intense external magnetic fields, electrical/optical injection of spin-polarized carriers/excitons or coupling with complex photonic metastructures. Here we report the creation of free-space chiral quantum light emitters via the nanoindentation of monolayer WSe2/NiPS3 heterostructures at zero external magnetic field. These quantum light emitters emit with a high degree of circular polarization (0.89) and single-photon purity (95%), independent of pump laser polarization. Scanning diamond nitrogen-vacancy microscopy and temperature-dependent magneto-photoluminescence studies reveal that the chiral quantum light emission arises from magnetic proximity interactions between localized excitons in the WSe2 monolayer and the out-of-plane magnetization of defects in the antiferromagnetic order of NiPS3, both of which are co-localized by strain fields associated with the nanoscale indentations.
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Data availability
Source data are provided with this paper. All other data supporting the plots within this paper and other findings of this study are available from the Supplementary Information or from the corresponding author upon reasonable request.
References
Žutić, I., Matos-Abiague, A., Scharf, B., Dery, H. & Belashchenko, K. Proximitized materials. Mater. Today 22, 85–107 (2019).
Huang, Y. et al. Room-temperature electron spin polarization exceeding 90% in an opto-spintronic semiconductor nanostructure via remote spin filtering. Nat. Photon. 15, 475–482 (2021).
Scharf, B., Xu, G., Matos-Abiague, A. & Žutić, I. Magnetic proximity effects in transition-metal dichalcogenides: converting excitons. Phys. Rev. Lett. 119, 127403 (2017).
Zhao, C. et al. Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field. Nat. Nanotechnol. 12, 757–762 (2017).
Shayan, K. et al. Magnetic proximity coupling of quantum emitters in WSe2 to van der Waals ferromagnets. Nano Lett. 19, 7301–7308 (2019).
Ciorciaro, L., Kroner, M., Watanabe, K., Taniguchi, T. & Imamoglu, A. Observation of magnetic proximity effect using resonant optical spectroscopy of an electrically tunable MoSe2/CrBr3 heterostructure. Phys. Rev. Lett. 124, 197401 (2020).
Lyons, T. P. et al. Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe2/CrBr3 van der Waals heterostructures. Nat. Commun. 11, 6021 (2020).
Mukherjee, A. et al. Observation of site-controlled localized charged excitons in CrI3/WSe2 heterostructures. Nat. Commun. 11, 5502 (2020).
Zhong, D. et al. Layer-resolved magnetic proximity effect in van der Waals heterostructures. Nat. Nanotechnol. 15, 187–191 (2020).
Zhong, D. et al. Van der Waals engineering of ferromagnetic semiconductor heterostructures for spin and valleytronics. Sci. Adv. 3, e1603113 (2017).
Liu, N. et al. Antiferromagnetic proximity coupling between semiconductor quantum emitters in WSe2 and van der Waals ferromagnets. Nanoscale 13, 832–841 (2021).
Tu, Z. et al. Spin–orbit coupling proximity effect in MoS2/Fe3GeTe2 heterostructures. Appl. Phys. Lett. 120, 043102 (2022).
Mak, K. F., Xiao, D. & Shan, J. Light–valley interactions in 2D semiconductors. Nat. Photon. 12, 451–460 (2018).
Aivazian, G. et al. Magnetic control of valley pseudospin in monolayer WSe2. Nat. Phys. 11, 148–152 (2015).
Lindemann, M. et al. Ultrafast spin-lasers. Nature 568, 212–215 (2019).
Seyler, K. L. et al. Signatures of moiré-trapped valley excitons in MoSe2/WSe2 heterobilayers. Nature 567, 66–70 (2019).
Tran, K. et al. Evidence for moiré excitons in van der Waals heterostructures. Nature 567, 71–75 (2019).
Chen, D., He, R., Cai, H., Liu, X. & Gao, W. Chiral single-photon generators. ACS Nano 15, 1912–1916 (2021).
Lodahl, P. et al. Chiral quantum optics. Nature 541, 473–480 (2017).
Li, H., Ruan, S. & Zeng, Y.-J. Intrinsic van der Waals magnetic materials from bulk to the 2D limit: new frontiers of spintronics. Adv. Mater. 31, 1900065 (2019).
Kim, S. Y. et al. Charge-spin correlation in van der Waals antiferromagnet NiPS3. Phys. Rev. Lett. 120, 136402 (2018).
Kang, S. et al. Coherent many-body exciton in van der Waals antiferromagnet NiPS3. Nature 583, 785–789 (2020).
Wang, X. et al. Spin-induced linear polarization of photoluminescence in antiferromagnetic van der Waals crystals. Nat. Mater. 20, 964–970 (2021).
Hwangbo, K. et al. Highly anisotropic excitons and multiple phonon bound states in a van der Waals antiferromagnetic insulator. Nat. Nanotechnol. 16, 655–660 (2021).
Ni, Z. et al. Imaging the Néel vector switching in the monolayer antiferromagnet MnPSe3 with strain-controlled Ising order. Nat. Nanotechnol. 16, 782–787 (2021).
Kim, K. et al. Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS3. Nat. Commun. 10, 345 (2019).
Clerk, A. A., Lehnert, K. W., Bertet, P., Petta, J. R. & Nakamura, Y. Hybrid quantum systems with circuit quantum electrodynamics. Nat. Phys. 16, 257–267 (2020).
Onga, M. et al. Antiferromagnet–semiconductor van der Waals heterostructures: interlayer interplay of exciton with magnetic ordering. Nano Lett. 20, 4625–4630 (2020).
Rosenberger, M. R. et al. Quantum calligraphy: writing single-photon emitters in a two-dimensional materials platform. ACS Nano 13, 904–912 (2019).
Turunen, M. et al. Quantum photonics with layered 2D materials. Nat. Rev. Phys. 4, 219–236 (2022).
Peyskens, F., Chakraborty, C., Muneeb, M., Van Thourhout, D. & Englund, D. Integration of single photon emitters in 2D layered materials with a silicon nitride photonic chip. Nat. Commun. 10, 4435 (2019).
Žutić, I. et al. Spin-lasers: spintronics beyond magnetoresistance. Solid State Commun. 316–317, 113949 (2020).
Makushko, P. et al. Flexomagnetism and vertically graded Néel temperature of antiferromagnetic Cr2O3 thin films. Nat. Commun. 13, 6745 (2022).
Andreev, A. F. Macroscopic magnetic fields of antiferromagnets. J. Exp. Theor. Phys. 63, 758–762 (1996).
Hedrich, N. et al. Nanoscale mechanics of antiferromagnetic domain walls. Nat. Phys. 17, 574–577 (2021).
Peterson, E. A., Haber, J. B. & Neaton, J. B. Superexchange-induced valley splitting in two-dimensional transition metal dichalcogenides: a first-principles study for rational design. Phys. Rev. B 104, 205421 (2021).
Doherty, M. W. et al. The nitrogen-vacancy colour centre in diamond. Phys. Rep. 528, 1–45 (2013).
Thiel, L. et al. Probing magnetism in 2D materials at the nanoscale with single-spin microscopy. Science 364, 973–976 (2019).
Htoon, H. et al. Anomalous circular polarization of photoluminescence spectra of individual CdSe nanocrystals in an applied magnetic field. Phys. Rev. Lett. 102, 017402 (2009).
Balasubramanian, G. et al. Nanoscale imaging magnetometry with diamond spins under ambient conditions. Nature 455, 648–651 (2008).
Hedrich, N., Rohner, D., Batzer, M., Maletinsky, P. & Shields, B. J. Parabolic diamond scanning probes for single-spin magnetic field imaging. Phys. Rev. Appl. 14, 064007 (2020).
Tetienne, J.-P. et al. The nature of domain walls in ultrathin ferromagnets revealed by scanning nanomagnetometry. Nat. Commun. 6, 6733 (2015).
Acknowledgements
This work was performed at the Center for Integrated Nanotechnologies, an Office of Science User Facility, operated for the US Department of Energy (DOE) Office of Science (OS). Los Alamos National Laboratory (LANL), an affirmative action equal opportunity employer, is managed by Triad National Security LLC for the US DOE’s NNSA, under contract 89233218CNA000001. Laboratory Directed Research and Development (LDRD) program 20200104DR provided primary support for the works of X.L., H.Z., A.P., N.S., S.A.C. and H.H. A.C.J. and V.C. acknowledge support from the DOE Basic Energy Sciences, QIS Infrastructure Development Program, Deterministic Placement and Integration of Quantum Defects. X.L., H.H. and S.A.C. also acknowledge partial support by the Quantum Science Center, a National QIS Research Center supported by the DOE, OS. J.C. and H.Z. also acknowledge partial support from LANL Director’s Postdoctoral Fellow Award. M.T.P. acknowledges support from LDRD awards 20210782ER and 20210640ECR. The National High Magnetic Field Laboratory is supported by the National Science Foundation (NSF) DMR-1644779, the State of Florida, and the US DOE. P.M., D.A.B., M.A.T. and P.R. acknowledge financial support from the National Centre of Competence in Research (NCCR) Quantum Science and Technology (QSIT), a competence centre funded by the Swiss National Science Foundation (SNF), by SNF project no. 188521, and by the ERC consolidator grant project QS2DM. We would like to acknowledge B. Zhou and X. Zhang for the magnetometry experiments using a near-surface ensemble of NV centres, and E. Peterson and C. A. Lane for insightful discussions on the magnetic-exchange proximity interaction.
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H.H. conceived and led the experiment. X.L., under the supervision of H.H., initiated the idea of using the nanoindentation method for enhancing the magnetic proximity effect along with the deterministic creation of localized QEs, prepared the samples and conducted the experiments. A.C.J. guided X.L. in creating nanoindentations in the WSe2/NiPS3 heterostructure and scanning probe microscopy studies. S.A.C. contributed the key idea of the temperature-dependent magneto-PL experiment and X.L. and J.C. conducted the experiment. H.Z., M.T.P. and V.C. assisted X.L. in a variety of optical spectroscopy experiments. N.S. and A.P. provided the theoretical model. D.A.B., M.A.T. and P.R. performed the NV magnetometry measurements under the supervision of P.M. H.H. and X.L. wrote the manuscript with the assistance of all the authors.
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Extended data
Extended Data Fig. 1 Experimental setup for low-temperature polarization resolved PL spectroscopy.
a. OBJ: Objective, DM: Dichroic mirror, QWP: quarter-wave plate, WP: Wollaston prism. For the linear polarization measurements, QWP is removed and two half-wave plates (HWP1 and HWP2) are inserted in excitation and collection channels. b. Schematic of the HBT experiment. BS: 50/50 beam splitter, APD1, APD2: Avalanche photo diodes, Counter: Hydra400 TCSPC module.
Extended Data Fig. 2 Control experiments.
a-d. Low temperature, σ+/- polarized PL spectra of WSe2 monolayer, region R1 of Fig. 1b(a, b) and un-indented WSe2/NiPS3 heterostructure, region R2 of Fig. 1b(c, d) excited by σ+ (a, c) and σ- (b, d) 514 nm laser. The data show no detectable DCP in the emission of both monolayer and un-indented WSe2/NiPS3 hetrostructure indicating that spin-polarized excitons injected at 514 nm were depolarized completely upon relaxation to the band-edge. e, f. Low temperature, linearly (S, P) polarized PL spectra (left panel) and plot of DLP as the function of polarization detection angle (right panel) for the sharp emission peak at 1.47 eV (e) and WSe2 exciton emission (f). (g) Upper Panel. Strong DLP (0.76) observed for 1.47 eV sharp emission peak is consistent with prior studies that attributed the emission to highly anisotropic excitons reflecting the emergence of AFM order in NiPS3. Lower Panel. PL of unstrained WSe2/NiPS3 heterostructure shows a weak degree of linear polarization consistent with the behavior of WSe2 monolayer.
Extended Data Fig. 3 Control experiment and invariance of circularly polarized PL emission under laser excitation of different polarization.
a. σ+/σ- polarization resolved PL spectra from WSe2/hBN/PMMA structures with similar nano-indents of Fig. 1, acquired under σ+(left) and σ- (right) polarized laser excitation, respectively. While localized exciton emission peaks of similar line shapes were created, no circularly polarized emission were detected. b. σ+/σ- polarization resolved PL spectra from 3 nano-indents of Fig. 1a, b acquired under σ+(left) and σ- (right) polarized laser excitation, respectively. While most nano-indents show circularly polarized localized exciton emission (bottom two panels), some show no circular polarization (top panels). When the excitation laser polarization is switched from σ+ to σ-, the polarities of the circularly polarized emission peak remain the same (peak marked a and b) but some quantitative change in DCPs as well as relative intensities of the localized PL peaks occur. c. Circularly polarized PL emission also remain qualitatively the same when the orientation of linearly polarized PL excitation is changed from 0 – 60 degree.
Extended Data Fig. 4 Spectral image and analysis of the spatial distribution of PL intensity.
a. PL spectral image of a nanoindentation in Fig. 1 a,b. σ+ and σ- PL emissions are simultaneously recorded on two different regions of the CCD array (upper). Degree of circular polarization (DoCP) spectrum calculated from integrated σ+ and σ- PL spectra (lower). b. Magnified spectra image of the region marked in (a). c. Blue data points: Intensity distribution of the localized emission peaks marked 1-5 in (b). By fitting the PL intensity distribution with Gaussian function (black fitted curves), we can determine the centroid of the emission peak with ± 0.1 pixel precision. The position of each peak and fitting error is listed next to the peak. Based on the magnification factor of the microscope objective (50X) and pixel dimensions of the CCD (20 μm), we can estimate that all peaks, marked 1- 5 originated from slightly different locations around the nano-indents. The separation between Peak 2 and 3 is ~ 50 nm.
Extended Data Fig. 5 Analyzing linear polarization of strain-engineered WSe2/NiPS3 heterostructure and distribution of linewidth of chiral quantum emitters and pump-dependent measurements.
a, top panel. σ+/σ- polarized PL spectra acquired under σ+ excitation. Inset. Zoom-in view of the NiPS3 anisotropic exciton peak displaying peak DCP of 0.4. lower panels. S and P linearly polarized PL spectra acquired at different polarization detection angles indicated in the panels. All three spectra are excited by σ+ polarized laser in the same way as the top panel. b. DLP of NiPS3 anisotropic exciton (red data points and trace of top panel) and PL peak 1-3 (lower panels) as the function of polarization detection angle. Black data points and trace plot DLP of NiPS3 anisotropic excitons in unstrained NiPS3. c. Histogram of the linewidths of chiral quantum light emitters yielding 3.6 ± 1.3 meV average and standard deviation, respectively. ~40% of the QEs display linewidth narrower than 3 meV. We believe the linewidth can be further minimized via encapsulation in hBN. Both linewidth and chirality show no notable dependence on laser excitation power. d. Pump-dependent study of a nanoindentation with two circularly polarized PL peaks. e, f. The plot of DCP and linewidth as the function of the pump displays a little change over 3 orders of magnitude change in pump power. The DCP of peaks a & b is calculated by taking the rise of the un-polarized PL background into account.
Extended Data Fig. 6 Another Chiral Quantum Light Emitter showing -0.7 DCP and 96% single photon purity.
a. Chiral PL spectra (σ+ (blue) and σ- (red)) of another indentation spot under linearly polarized laser excitation showing >70% of DCP. b. PL intensity time trace, c. PL decay curve, d. 2nd order photon correlation trace collected at 10 K showing a g(2)(0) = 0.04.
Extended Data Fig. 7 Room temperature (RT) scanning diamond NV microscopy study of indented NiPS3.
a. Topographical image of the indentation shown in Fig. 3c. The RT scanning NV system utilized a slightly sharper NV probe yielding a higher resolution topographical image. b. Magnetic field image of the same area showing only the noise.
Extended Data Fig. 8 Complete data set for Fig. 4a.
Center panel. Low-temperature σ+ and σ- polarized PL spectra acquired under -6.0 T to +6.0 T external magnetic field applied perpendicular to the sample plane. Left and right panels. Zoom-in view of the gray and red spectra ranges of the center panels. Because magneto-PL spectra were acquired under 633 nm σ+ laser excitation, a weak DCP is observed at zero B field. A weak magnetic field-dependent change in DCP likely resulting from field-induced polarization of localized excitons is also observed in the 1.65 to 1.70 eV spectral range.
Extended Data Fig. 9 Complete data set for Figs. 4c and 4d.
Extended Data Fig. 10 Observation of Chiral Localized Exciton Emission from WSe2/FePS3 and WSe2/MnPS3 heterostructures with nano-indents.
a-b. Optical images of the WSe2/FePS3 (a) and WSe2/MnPS3 (b) heterostructures with nano-indents. c-d. σ+ and σ- polarized PL spectra acquired under linearly polarized laser excitation at 4 K from two different nano-indents of WSe2/FePS3 (c) and WSe2/MnPS3 (d), respectively.
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Discussion on competition between anisotropic exchange and Zeeman splitting.
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Li, X., Jones, A.C., Choi, J. et al. Proximity-induced chiral quantum light generation in strain-engineered WSe2/NiPS3 heterostructures. Nat. Mater. 22, 1311–1316 (2023). https://doi.org/10.1038/s41563-023-01645-7
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DOI: https://doi.org/10.1038/s41563-023-01645-7
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