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Kim SW, Kim HJ, Cheon S, Kim TH. Circular Dichroism of Emergent Chiral Stacking Orders in Quasi-One-Dimensional Charge Density Waves. PHYSICAL REVIEW LETTERS 2022; 128:046401. [PMID: 35148124 DOI: 10.1103/physrevlett.128.046401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Chirality-driven optical properties in charge density waves are of fundamental and practical importance. Here, we investigate the interaction between circularly polarized light and emergent chiral stacking orders in quasi-one-dimensional (quasi-1D) charge-density waves (CDWs) with density-functional theory calculations. In our specific system, self-assembled In nanowires on a Si(111) surface, spontaneous mirror symmetry breaking leads to four symmetrically distinct degenerate quasi-1D CDW structures, which exhibit geometrical chirality. Such geometrical chirality may naturally induce optically active phenomena even when the quasi-1D CDW structures are stacked perpendicular to the CDW chain direction. Indeed, we find that left- and right-chiral stacking orders show distinct circular dichroism responses while a nonchiral stacking order has no circular dichroism. Such optical responses are attributed to the existence of glide mirror symmetry of the CDW stacking orders. Our findings suggest that the CDW chiral stacking orders can lead to diverse active optical phenomena such as chirality-dependent circular dichroism, which can be observed in scanning tunneling luminescence measurements with circularly polarized light.
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Affiliation(s)
- Sun-Woo Kim
- Department of Physics and Research Institute for Natural Science, Hanyang University, Seoul 04763, Korea
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Hyun-Jung Kim
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
| | - Sangmo Cheon
- Department of Physics and Research Institute for Natural Science, Hanyang University, Seoul 04763, Korea
- Institute for High Pressure, Hanyang University, Seoul 04763, Korea
| | - Tae-Hwan Kim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
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Song SK, Samad A, Wippermann S, Yeom HW. Dynamical Metal to Charge-Density-Wave Junctions in an Atomic Wire Array. NANO LETTERS 2019; 19:5769-5773. [PMID: 31276408 DOI: 10.1021/acs.nanolett.9b02438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigated the atomic scale electronic phase separation emerging from a quasi-1D charge-density-wave (CDW) state of the In atomic wire array on a Si(111) surface. Spatial variations of the CDW gap and amplitude are quantified for various interfaces of metallic and insulating CDW domains by scanning tunneling microscopy and spectroscopy (STS). The strong anisotropy in the metal-insulator junctions is revealed with an order of magnitude difference in the interwire and intrawire junction lengths of 0.4 and 7 nm, respectively. The intrawire junction length is reduced dramatically by an atomic scale impurity, indicating the tunability of the metal-insulator junction in an atomic scale. Density functional theory calculations disclose the dynamical nature of the intrawire junction formation and tunability.
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Affiliation(s)
- Sun Kyu Song
- Center for Artificial Low Dimensional Electronic Systems , Institute for Basic Science (IBS) , Pohang 37673 , Republic of Korea
- Department of Physics , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea
| | - Abdus Samad
- Max-Planck-Institut für Eisenforschung GmbH , Düsseldorf 40237 , Germany
| | - Stefan Wippermann
- Max-Planck-Institut für Eisenforschung GmbH , Düsseldorf 40237 , Germany
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems , Institute for Basic Science (IBS) , Pohang 37673 , Republic of Korea
- Department of Physics , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea
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Ren XY, Kim HJ, Niu CY, Jia Y, Cho JH. Origin of Symmetric Dimer Images of Si(001) Observed by Low-Temperature Scanning Tunneling Microscopy. Sci Rep 2016; 6:27868. [PMID: 27292000 PMCID: PMC4904415 DOI: 10.1038/srep27868] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/26/2016] [Indexed: 11/09/2022] Open
Abstract
It has been a long-standing puzzle why buckled dimers of the Si(001) surface appeared symmetric below ~20 K in scanning tunneling microscopy (STM) experiments. Although such symmetric dimer images were concluded to be due to an artifact induced by STM measurements, its underlying mechanism is still veiled. Here, we demonstrate, based on a first-principles density-functional theory calculation, that the symmetric dimer images are originated from the flip-flop motion of buckled dimers, driven by quantum tunneling (QT). It is revealed that at low temperature the tunneling-induced surface charging with holes reduces the energy barrier for the flipping of buckled dimers, thereby giving rise to a sizable QT-driven frequency of the flip-flop motion. However, such a QT phenomenon becomes marginal in the tunneling-induced surface charging with electrons. Our findings provide an explanation for low-temperature STM data that exhibits apparent symmetric (buckled) dimer structure in the filled-state (empty-state) images.
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Affiliation(s)
- Xiao-Yan Ren
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Korea.,School of Mechanical and Electrical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, China
| | - Hyun-Jung Kim
- Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Korea.,Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722, Korea
| | - Chun-Yao Niu
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Center for Advanced Analysis and Computational Science, Zhengzhou University, Zhengzhou 45001, China
| | - Yu Jia
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Center for Advanced Analysis and Computational Science, Zhengzhou University, Zhengzhou 45001, China
| | - Jun-Hyung Cho
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China.,Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, Korea.,International Center for Quantum Design of Functional Materials (ICQD), HFNL, University of Science and Technology of China, Hefei, Anhui 230026, China
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