Programming correlated magnetic states with gate-controlled moiré geometry

Understanding quantum many-body systems is at the heart of condensed matter physics. The ability to control the underlying lattice geometry of a system, and thus its many-body interactions, would enable the realization of and transition between emergent quantum ground states. Here, we report in-situ gate switching between honeycomb and triangular lattice geometries of an electron many-body Hamiltonian in R-stacked MoTe2 moir\'e bilayers, resulting in switchable magnetic exchange interactions. At zero electric field, we observe a correlated ferromagnetic insulator near one hole per moir\'e unit cell ({\nu}=-1), i.e., a quarter-filled honeycomb lattice, with a widely tunable Curie temperature up to 14K. Fully polarizing layer pseudospin via electric field switches the system into a half-filled triangular lattice with antiferromagnetic interactions. Further doping this layer-polarized superlattice introduces carriers into the empty layer, tuning the antiferromagnetic exchange interaction back to ferromagnetic. Our work demonstrates R-stacked MoTe2 moir\'es to be a new laboratory for engineering correlated states with nontrivial topology.

[1]  Ziliang Ye,et al.  Optically probing the asymmetric interlayer coupling in rhombohedral-stacked MoS2 bilayer , 2022, 2209.06966.

[2]  J. Shan,et al.  A tunable bilayer Hubbard model in twisted WSe2 , 2022, Nature Nanotechnology.

[3]  A. Potter,et al.  Gate-tunable heavy fermion quantum criticality in a moiré Kondo lattice , 2021, Physical Review B.

[4]  Kenji Watanabe,et al.  Interfacial ferroelectricity in rhombohedral-stacked bilayer transition metal dichalcogenides , 2021, Nature Nanotechnology.

[5]  Kenji Watanabe,et al.  Imaging two-dimensional generalized Wigner crystals , 2021, Nature.

[6]  Kenji Watanabe,et al.  Excitonic and Valley-Polarization Signatures of Fractional Correlated Electronic Phases in a WSe_{2}/WS_{2} Moiré Superlattice. , 2021, Physical review letters.

[7]  T. Devakul,et al.  Magic in twisted transition metal dichalcogenide bilayers , 2021, Nature Communications.

[8]  Kenji Watanabe,et al.  Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice , 2021, Nature Communications.

[9]  V. Fal’ko,et al.  Multifaceted moiré superlattice physics in twisted WSe2 bilayers , 2021, Physical Review B.

[10]  A. Millis,et al.  Hartree-Fock study of the moir\'e Hubbard model for twisted bilayer transition metal dichalcogenides , 2021, 2105.11883.

[11]  Yang Zhang,et al.  Electronic structures, charge transfer, and charge order in twisted transition metal dichalcogenide bilayers , 2021 .

[12]  A. Millis,et al.  Quantum criticality in twisted transition metal dichalcogenides , 2021, Nature.

[13]  U. Kumar,et al.  Spontaneous fractional Chern insulators in transition metal dichalcogenide moiré superlattices , 2021, Physical Review Research.

[14]  Kenji Watanabe,et al.  Correlated insulating states at fractional fillings of the WS2/WSe2 moiré lattice , 2020, Nature Physics.

[15]  S. Trebst,et al.  Realization of nearly dispersionless bands with strong orbital anisotropy from destructive interference in twisted bilayer MoS2 , 2020, Nature Communications.

[16]  J. Shan,et al.  Correlated insulating states at fractional fillings of moiré superlattices , 2020, Nature.

[17]  S. Das Sarma,et al.  Quantum phase diagram of a Moiré-Hubbard model , 2020, Physical Review B.

[18]  Kenji Watanabe,et al.  Correlated electronic phases in twisted bilayer transition metal dichalcogenides , 2020, Nature Materials.

[19]  S. Das Sarma,et al.  Band topology, Hubbard model, Heisenberg model, and Dzyaloshinskii-Moriya interaction in twisted bilayer WSe2 , 2020, 2004.04168.

[20]  Kenji Watanabe,et al.  Strongly correlated electrons and hybrid excitons in a moiré heterostructure , 2020, Nature.

[21]  M. Lukin,et al.  Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe2/MoSe2 bilayers , 2020, Nature Nanotechnology.

[22]  Kenji Watanabe,et al.  Flat bands in twisted bilayer transition metal dichalcogenides , 2019, Nature Physics.

[23]  Kenji Watanabe,et al.  Mott and generalized Wigner crystal states in WSe2/WS2 moiré superlattices , 2019, Nature.

[24]  J. Zhu,et al.  Intrinsic quantized anomalous Hall effect in a moiré heterostructure , 2019, Science.

[25]  W. Yao,et al.  Giant magnetic field from moiré induced Berry phase in homobilayer semiconductors , 2019, National science review.

[26]  M. Xie,et al.  Nature of the Correlated Insulator States in Twisted Bilayer Graphene. , 2018, Physical review letters.

[27]  M. Kastner,et al.  Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene , 2019, Science.

[28]  A. MacDonald,et al.  Topological Insulators in Twisted Transition Metal Dichalcogenide Homobilayers. , 2018, Physical review letters.

[29]  E. Tutuc,et al.  Hubbard Model Physics in Transition Metal Dichalcogenide Moiré Bands. , 2018, Physical review letters.

[30]  Mit H. Naik,et al.  Ultraflatbands and Shear Solitons in Moiré Patterns of Twisted Bilayer Transition Metal Dichalcogenides. , 2018, Physical review letters.

[31]  Takashi Taniguchi,et al.  Unconventional superconductivity in magic-angle graphene superlattices , 2018, Nature.

[32]  C. Robert,et al.  Excitonic properties of semiconducting monolayer and bilayer MoTe2 , 2016, 1606.03337.

[33]  Yuerui Lu,et al.  Robust Excitons and Trions in Monolayer MoTe2. , 2015, ACS nano.

[34]  A. Morpurgo,et al.  Indirect-to-direct band gap crossover in few-layer MoTe₂. , 2015, Nano letters.

[35]  Tao E. Li.  Spontaneous quantum Hall effect in quarter-doped Hubbard model on honeycomb lattice and its possible realization in doped graphene system , 2011, 1103.2420.