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Uto T, Evrard B, Watanabe K, Taniguchi T, Kroner M, İmamoğlu A. Interaction-Induced ac Stark Shift of Exciton-Polaron Resonances. Phys Rev Lett 2024; 132:056901. [PMID: 38364159 DOI: 10.1103/physrevlett.132.056901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 12/20/2023] [Accepted: 01/04/2024] [Indexed: 02/18/2024]
Abstract
Laser-induced shift of atomic states due to the ac Stark effect has played a central role in cold-atom physics and facilitated their emergence as analog quantum simulators. Here, we explore this phenomenon in an atomically thin layer of semiconductor MoSe_{2}, which we embedded in a heterostructure enabling charge tunability. Shining an intense pump laser with a small detuning from the material resonances, we generate a large population of virtual collective excitations and achieve a regime where interactions with this background population are the leading contribution to the ac Stark shift. Using this technique we study how itinerant charges modify-and dramatically enhance-the interactions between optical excitations. In particular, our experiments show that the interaction between attractive polarons could be more than an order of magnitude stronger than those between bare excitons.
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Affiliation(s)
- T Uto
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - B Evrard
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - K Watanabe
- Research Center for Electronic and Optical Materials, NIMS, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- Research Center for Electronic and Optical Materials, NIMS, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - M Kroner
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A İmamoğlu
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
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Ciorciaro L, Smoleński T, Morera I, Kiper N, Hiestand S, Kroner M, Zhang Y, Watanabe K, Taniguchi T, Demler E, İmamoğlu A. Kinetic magnetism in triangular moiré materials. Nature 2023; 623:509-513. [PMID: 37968525 PMCID: PMC10651480 DOI: 10.1038/s41586-023-06633-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 09/12/2023] [Indexed: 11/17/2023]
Abstract
Magnetic properties of materials ranging from conventional ferromagnetic metals to strongly correlated materials such as cuprates originate from Coulomb exchange interactions. The existence of alternate mechanisms for magnetism that could naturally facilitate electrical control has been discussed theoretically1-7, but an experimental demonstration8 in an extended system has been missing. Here we investigate MoSe2/WS2 van der Waals heterostructures in the vicinity of Mott insulator states of electrons forming a frustrated triangular lattice and observe direct evidence of magnetic correlations originating from a kinetic mechanism. By directly measuring electronic magnetization through the strength of the polarization-selective attractive polaron resonance9,10, we find that when the Mott state is electron-doped, the system exhibits ferromagnetic correlations in agreement with the Nagaoka mechanism.
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Affiliation(s)
- L Ciorciaro
- Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland
| | - T Smoleński
- Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland
| | - I Morera
- Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona, Barcelona, Spain
- Institut de Ciències del Cosmos, Universitat de Barcelona, Barcelona, Spain
| | - N Kiper
- Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland
| | - S Hiestand
- Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland
| | - M Kroner
- Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland
| | - Y Zhang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA
- Min H. Kao Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, USA
| | - K Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, Tsukuba, Japan
| | - T Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - E Demler
- Institute for Theoretical Physics, ETH Zürich, Zürich, Switzerland
| | - A İmamoğlu
- Institute for Quantum Electronics, ETH Zürich, Zürich, Switzerland.
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Smoleński T, Watanabe K, Taniguchi T, Kroner M, Imamoğlu A. Spin-Valley Relaxation and Exciton-Induced Depolarization Dynamics of Landau-Quantized Electrons in MoSe_{2} Monolayer. Phys Rev Lett 2022; 128:127402. [PMID: 35394309 DOI: 10.1103/physrevlett.128.127402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/05/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Nonequilibrium dynamics of strongly correlated systems constitutes a fascinating problem of condensed matter physics with many open questions. Here, we investigate the relaxation dynamics of Landau-quantized electron system into spin-valley polarized ground state in a gate-tunable MoSe_{2} monolayer subjected to a strong magnetic field. The system is driven out of equilibrium with optically injected excitons that depolarize the electron spins and the subsequent electron spin-valley relaxation is probed in time-resolved experiments. We demonstrate that both the relaxation and light-induced depolarization rates at millikelvin temperatures sensitively depend on the Landau level filling factor: the relaxation is enhanced whenever the electrons form an integer quantum Hall liquid and slows down appreciably at noninteger fillings, while the depolarization rate exhibits an opposite behavior. Our findings suggest that spin-valley dynamics may be used as a tool to investigate the interplay between the effects of disorder and strong interactions in the electronic ground state.
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Affiliation(s)
- T Smoleński
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - M Kroner
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Imamoğlu
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
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Smoleński T, Cotlet O, Popert A, Back P, Shimazaki Y, Knüppel P, Dietler N, Taniguchi T, Watanabe K, Kroner M, Imamoglu A. Interaction-Induced Shubnikov-de Haas Oscillations in Optical Conductivity of Monolayer MoSe_{2}. Phys Rev Lett 2019; 123:097403. [PMID: 31524484 DOI: 10.1103/physrevlett.123.097403] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Indexed: 06/10/2023]
Abstract
We report polarization-resolved resonant reflection spectroscopy of a charge-tunable atomically thin valley semiconductor hosting tightly bound excitons coupled to a dilute system of fully spin- and valley-polarized holes in the presence of a strong magnetic field. We find that exciton-hole interactions manifest themselves in hole-density dependent, Shubnikov-de Haas-like oscillations in the energy and line broadening of the excitonic resonances. These oscillations are evidenced to be precisely correlated with the occupation of Landau levels, thus demonstrating that strong interactions between the excitons and Landau-quantized itinerant carriers enable optical investigation of quantum-Hall physics in transition metal dichalcogenides.
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Affiliation(s)
- T Smoleński
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - O Cotlet
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Popert
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - P Back
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Y Shimazaki
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - P Knüppel
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - N Dietler
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - M Kroner
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Imamoglu
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
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Högele A, Kroner M, Latta C, Claassen M, Carusotto I, Bulutay C, Imamoglu A. Dynamic nuclear spin polarization in the resonant laser excitation of an InGaAs quantum dot. Phys Rev Lett 2012; 108:197403. [PMID: 23003088 DOI: 10.1103/physrevlett.108.197403] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Indexed: 06/01/2023]
Abstract
Resonant optical excitation of lowest-energy excitonic transitions in self-assembled quantum dots leads to nuclear spin polarization that is qualitatively different from the well-known optical orientation phenomena. By carrying out a comprehensive set of experiments, we demonstrate that nuclear spin polarization manifests itself in quantum dots subjected to finite external magnetic field as locking of the higher energy Zeeman transition to the driving laser field, as well as the avoidance of the resonance condition for the lower energy Zeeman branch. We interpret our findings on the basis of dynamic nuclear spin polarization originating from noncollinear hyperfine interaction and find excellent agreement between experiment and theory. Our results provide evidence for the significance of noncollinear hyperfine processes not only for nuclear spin diffusion and decay, but also for buildup dynamics of nuclear spin polarization in a coupled electron-nuclear spin system.
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Affiliation(s)
- A Högele
- Fakultät für Physik and CeNS, Ludwig-Maximilians-Universität München, D-80539 München, Germany
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Dalgarno PA, Ediger M, Gerardot BD, Smith JM, Seidl S, Kroner M, Karrai K, Petroff PM, Govorov AO, Warburton RJ. Optically induced hybridization of a quantum dot state with a filled continuum. Phys Rev Lett 2008; 100:176801. [PMID: 18518317 DOI: 10.1103/physrevlett.100.176801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 01/14/2008] [Indexed: 05/26/2023]
Abstract
We present an optical signature of a hybridization between a localized quantum dot state and a filled continuum. Radiative recombination of the negatively charged trion in a single quantum dot leaves behind a single electron. We show that in two regions of vertical electric field, the electron hybridizes with a continuum through a tunneling interaction. The hybridization manifests itself through an unusual voltage dependence of the emission energy and a non-Lorentzian line shape, features which we reproduce with a theory based on the Anderson Hamiltonian.
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Affiliation(s)
- P A Dalgarno
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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Kroner M, Govorov AO, Remi S, Biedermann B, Seidl S, Badolato A, Petroff PM, Zhang W, Barbour R, Gerardot BD, Warburton RJ, Karrai K. Erratum: The nonlinear Fano effect. Nature 2008. [DOI: 10.1038/nature06728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Schmidt U, Griesser H, Haas G, Kroner M, Riedl B, Schumacher A, Sutoris F, Haupt A, Emling F. Synthesis and cytostatic activities of didemnin derivatives. J Pept Res 1999; 54:146-61. [PMID: 10461749 DOI: 10.1034/j.1399-3011.1999.00097.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The highly cytostatic didemnins contain a 23-membered cyclopeptolide with a side chain attached to the backbone through the amine group of threonine. Thirty-six derivatives varying the side chain were prepared, but only compounds with D-MeLeu attached to threonine show remarkable biological activities. To protect the macrocycle from degradation by lipases the two ester bonds were replaced successively by amide bonds. Although these variations have a major effect on the conformation and rigidity of the ring, the compound which contains exclusively amide bonds is highly active, equivalent to acetyl-didemnin A.
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Affiliation(s)
- U Schmidt
- Institute of Organic Chemistry, University of Stuttgart, Germany
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Kuhn W, Schmalfeldt B, Pache L, Späthe K, Ulm K, Renziehausen K, Nöschel H, Canzler E, Richter B, Kroner M, Tilch G, Janicke F, Graeff H. Disease-adapted relapse therapy for ovarian cancer: results of a prospective study. Int J Oncol 1998; 13:57-63. [PMID: 9625803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Primary therapy of advanced ovarian cancer is standardized, the therapy in relapsed ovarian cancer however is still controversial. In a prospective study the benefit of secondary surgery and/or second-line chemotherapy were evaluated. 139 patients with relapsed ovarian cancer were stratified according to a treatment plan: patients with early relapse (recurrence-free interval 12 months) or primary progression during chemotherapy (n=43) were treated chemotherapeutically with etoposide (p.o. vs. i.v.). Patients with late relapse (recurrence-free interval >12 months, n=96) were referred, if possible, to a secondary debulking operation, followed by a platinum-based chemotherapy. Remission-rate, toxicity and survival time were analyzed. Median survival time in the <early relapse> group was 15 months compared to 30 months in patients with late relapse (p=0.0004). Within the <late relapse> group patients with secondary debulking and chemotherapy (n=59) had a statistically significant survival advantage compared to patients who had only chemotherapy (n=37) (38 vs. 12 months, p<0.0001). The unfavorable group of patients with early relapse should be treated chemotherapeutically, whereas in patients with late relapse a secondary debulking seems to improve prognosis.
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Affiliation(s)
- W Kuhn
- Frauenklinik der Technischen Universität München, Klinikum rechts der Isar, D-81675 München, Germany
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