Ji-Hee Kim, Gunnar Schönhoff, Michael Lorke, Tim O. Wehling, Ki-Ju Yee
{"title":"通过极子形成实现 MoTe2 薄膜中的超快可逆相工程","authors":"Ji-Hee Kim, Gunnar Schönhoff, Michael Lorke, Tim O. Wehling, Ki-Ju Yee","doi":"10.1007/s40042-024-01077-9","DOIUrl":null,"url":null,"abstract":"<div><p>The emergence of various polymorphs in two-dimensional transition metal dichalcogenides provides an opportunity for robust phase engineering by temperature, strain, laser irradiation, and external charge doping (Keum in Nat. Phys. 11:482, 2015; Song in Nano Lett. 16:188, 2016; Cho in Science 349:625, 2015; Kim in Nano Lett. 17:3363, 2017). This provides means to develop homojunction of metal–semiconductor, enhance mobility, reduce contact resistance, and observe novel quantum critical phenomena in mesoscopic systems. The rich physics paves the way for ultrafast light-induced switching/memory devices and optical data processing in optoelectronics. However, the fundamental temporal evolution of the laser-driven phase transformation, in particular regarding heat and charge carriers, remains elusive. We report an ultrafast reversible structural transformation in MoTe<sub>2</sub> by coherent phonon dynamics through polaron formation at room temperature. At a high photon density, the generated coherent phonons are coupled with excitons to form polarons. The strong exciton–phonon coupling disturbs and dephases the coherent phonons of the semiconducting 2H phase in MoTe<sub>2</sub>, and generates lattice distortions to further stabilize new coherent phonons of the metallic 1T’-phase, manifested by the emergence of the corresponding phonons in each phase. This structural transformation is fully reversible within a few picoseconds by switching on/off the laser. The nonlinear response of the phonon intensity to the excited carrier density in the intermediate region indicates a gradual structural transformation through coexisting 2H and 1T’ phases.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40042-024-01077-9.pdf","citationCount":"0","resultStr":"{\"title\":\"Ultrafast reversible phase engineering in MoTe2 thin film via polaron formation\",\"authors\":\"Ji-Hee Kim, Gunnar Schönhoff, Michael Lorke, Tim O. Wehling, Ki-Ju Yee\",\"doi\":\"10.1007/s40042-024-01077-9\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The emergence of various polymorphs in two-dimensional transition metal dichalcogenides provides an opportunity for robust phase engineering by temperature, strain, laser irradiation, and external charge doping (Keum in Nat. Phys. 11:482, 2015; Song in Nano Lett. 16:188, 2016; Cho in Science 349:625, 2015; Kim in Nano Lett. 17:3363, 2017). This provides means to develop homojunction of metal–semiconductor, enhance mobility, reduce contact resistance, and observe novel quantum critical phenomena in mesoscopic systems. The rich physics paves the way for ultrafast light-induced switching/memory devices and optical data processing in optoelectronics. However, the fundamental temporal evolution of the laser-driven phase transformation, in particular regarding heat and charge carriers, remains elusive. We report an ultrafast reversible structural transformation in MoTe<sub>2</sub> by coherent phonon dynamics through polaron formation at room temperature. At a high photon density, the generated coherent phonons are coupled with excitons to form polarons. The strong exciton–phonon coupling disturbs and dephases the coherent phonons of the semiconducting 2H phase in MoTe<sub>2</sub>, and generates lattice distortions to further stabilize new coherent phonons of the metallic 1T’-phase, manifested by the emergence of the corresponding phonons in each phase. This structural transformation is fully reversible within a few picoseconds by switching on/off the laser. The nonlinear response of the phonon intensity to the excited carrier density in the intermediate region indicates a gradual structural transformation through coexisting 2H and 1T’ phases.</p></div>\",\"PeriodicalId\":677,\"journal\":{\"name\":\"Journal of the Korean Physical Society\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2024-05-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://link.springer.com/content/pdf/10.1007/s40042-024-01077-9.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the Korean Physical Society\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s40042-024-01077-9\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the Korean Physical Society","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s40042-024-01077-9","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
二维过渡金属二粲化物中各种多晶体的出现为通过温度、应变、激光照射和外部电荷掺杂进行稳健的相工程提供了机会(Keum 在 Nat.11:482, 2015; Song in Nano Lett.16:188, 2016; Cho in Science 349:625, 2015; Kim in Nano Lett.17:3363, 2017).这为开发金属-半导体同质结、提高迁移率、降低接触电阻以及观察介观系统中的新量子临界现象提供了手段。丰富的物理学为光电子学中的超快光诱导开关/存储器件和光数据处理铺平了道路。然而,激光驱动相变的基本时间演化,尤其是热量和电荷载流子方面的演化,仍然难以捉摸。我们报告了 MoTe2 在室温下通过极子形成的相干声子动力学发生的超快可逆结构转变。在高光子密度下,产生的相干声子与激子耦合形成极子。强烈的激子-声子耦合扰乱并消解了 MoTe2 中半导体 2H 相的相干声子,并产生晶格畸变,进一步稳定了金属 1T'- 相的新相干声子,表现为在每个相中都出现了相应的声子。通过开关激光,这种结构转变在几皮秒内完全可逆。声子强度对中间区域激发载流子密度的非线性响应表明,2H 相和 1T' 相共存的结构转变是渐进的。
Ultrafast reversible phase engineering in MoTe2 thin film via polaron formation
The emergence of various polymorphs in two-dimensional transition metal dichalcogenides provides an opportunity for robust phase engineering by temperature, strain, laser irradiation, and external charge doping (Keum in Nat. Phys. 11:482, 2015; Song in Nano Lett. 16:188, 2016; Cho in Science 349:625, 2015; Kim in Nano Lett. 17:3363, 2017). This provides means to develop homojunction of metal–semiconductor, enhance mobility, reduce contact resistance, and observe novel quantum critical phenomena in mesoscopic systems. The rich physics paves the way for ultrafast light-induced switching/memory devices and optical data processing in optoelectronics. However, the fundamental temporal evolution of the laser-driven phase transformation, in particular regarding heat and charge carriers, remains elusive. We report an ultrafast reversible structural transformation in MoTe2 by coherent phonon dynamics through polaron formation at room temperature. At a high photon density, the generated coherent phonons are coupled with excitons to form polarons. The strong exciton–phonon coupling disturbs and dephases the coherent phonons of the semiconducting 2H phase in MoTe2, and generates lattice distortions to further stabilize new coherent phonons of the metallic 1T’-phase, manifested by the emergence of the corresponding phonons in each phase. This structural transformation is fully reversible within a few picoseconds by switching on/off the laser. The nonlinear response of the phonon intensity to the excited carrier density in the intermediate region indicates a gradual structural transformation through coexisting 2H and 1T’ phases.
期刊介绍:
The Journal of the Korean Physical Society (JKPS) covers all fields of physics spanning from statistical physics and condensed matter physics to particle physics. The manuscript to be published in JKPS is required to hold the originality, significance, and recent completeness. The journal is composed of Full paper, Letters, and Brief sections. In addition, featured articles with outstanding results are selected by the Editorial board and introduced in the online version. For emphasis on aspect of international journal, several world-distinguished researchers join the Editorial board. High quality of papers may be express-published when it is recommended or requested.