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Hernandez FG, Baydin A, Chaudhary S, Tay F, Katayama I, Takeda J, Nojiri H, Okazaki AK, Rappl PH, Abramof E, Rodriguez-Vega M, Fiete GA, Kono J. Observation of interplay between phonon chirality and electronic band topology. SCIENCE ADVANCES 2023; 9:eadj4074. [PMID: 38100589 PMCID: PMC10848715 DOI: 10.1126/sciadv.adj4074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 11/15/2023] [Indexed: 12/17/2023]
Abstract
The recently demonstrated chiral modes of lattice motion carry angular momentum and therefore directly couple to magnetic fields. Notably, their magnetic moments are predicted to be strongly influenced by electronic contributions. Here, we have studied the magnetic response of transverse optical phonons in a set of Pb1-xSnxTe films, which is a topological crystalline insulator for x > 0.32 and has a ferroelectric transition at an x-dependent critical temperature. Polarization-dependent terahertz magnetospectroscopy measurements revealed Zeeman splittings and diamagnetic shifts, demonstrating a large phonon magnetic moment. Films in the topological phase exhibited phonon magnetic moment values that were larger than those in the topologically trivial samples by two orders of magnitude. Furthermore, the sign of the effective phonon g-factor was opposite in the two phases, a signature of the topological transition according to our model. These results strongly indicate the existence of interplay between the magnetic properties of chiral phonons and the topology of the electronic band structure.
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Affiliation(s)
| | - Andrey Baydin
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
- Smalley-Curl Institute, Rice University, Houston, TX 77005, USA
| | - Swati Chaudhary
- Department of Physics, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Physics, Northeastern University, Boston, MA 02115, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Fuyang Tay
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
- Applied Physics Graduate Program, Smalley-Curl Institute, Rice University, Houston, TX 77005, USA
| | - Ikufumi Katayama
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan
| | - Jun Takeda
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Anderson K. Okazaki
- Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP 12201-970, Brazil
| | - Paulo H. O. Rappl
- Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP 12201-970, Brazil
| | - Eduardo Abramof
- Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP 12201-970, Brazil
| | - Martin Rodriguez-Vega
- Department of Physics, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Gregory A. Fiete
- Department of Physics, Northeastern University, Boston, MA 02115, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Junichiro Kono
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
- Smalley-Curl Institute, Rice University, Houston, TX 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
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Mella JD, Calvo HL, Foa Torres LEF. Entangled States Induced by Electron-Phonon Interaction in Two-Dimensional Materials. NANO LETTERS 2023. [PMID: 37984421 DOI: 10.1021/acs.nanolett.3c03316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
We report on the effects of electron-phonon interaction in materials such as graphene, showing that it enables the formation of a gap bridged by unique edge states. These states exhibit a distinctive locking among propagation direction, valley, and phonon mode, allowing for the generation of electron-phonon entangled states whose parts can be easily split. We discuss the effect of the chiral atomic motion in the zone boundary phonons leading to this effect. Our findings shed light on how to harness these unconventional states in quantum research.
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Affiliation(s)
- José D Mella
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, 8370448 Santiago, Chile
- School of Engineering and Sciences, Universidad Adolfo Ibáñez, 7941169 Santiago, Chile
| | - Hernán L Calvo
- Instituto de Física Enrique Gaviola (CONICET) and FaMAF, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
| | - Luis E F Foa Torres
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, 8370448 Santiago, Chile
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