Chemistry of Materials最新文献

Revealing the Self-Doped Nature of CdxAgySe Quantum Dots under Cation Exchange Control 揭示阳离子交换控制下CdxAgySe量子点的自掺杂性质

IF 8.6 2区材料科学

Chemistry of Materials Pub Date : 2025-06-26 DOI: 10.1021/acs.chemmater.4c03484

Jin Hyeok Lee, So Young Eom, Hyeong Seok Kang, Haemin Song, Soeun Jeon, Si Yu Kim, Kwang Seob Jeong

{"title":"Revealing the Self-Doped Nature of CdxAgySe Quantum Dots under Cation Exchange Control","authors":"Jin Hyeok Lee, So Young Eom, Hyeong Seok Kang, Haemin Song, Soeun Jeon, Si Yu Kim, Kwang Seob Jeong","doi":"10.1021/acs.chemmater.4c03484","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03484","url":null,"abstract":"Metal-chalcogenide nanocrystals inevitably experience a state with a nonstoichiometric ratio during their growth. Considering that a few atoms function as dopants, the nonstoichiometric composition can determine the fundamental properties of the materials. Such a stoichiometry change in real time is extremely fast, and thereby, the product lies in an energetically stable state with a stoichiometric integral ratio. The phenomenon becomes dramatic for the cation-exchange reaction. Thus, the cation-exchange reaction with a controllable exchange rate can be an excellent way to generate the unexplored metastable state with a nonstoichiometry where interesting optical and electrical properties appear. Here, we report cation-exchanged CdxAgySe quantum dots (QDs) at a metastable self-doped state exhibiting intraband transition in the mid-wavelength infrared (mid-IR) regime. The state is successfully captured by controlling the reaction rate of the cation exchange and analyzed using short-wavelength and mid-IR photoluminescence spectroscopy under cryo-temperature, transmission electron microscopy, nuclear magnetic resonance, X-ray diffraction analysis, and energy-dispersive X-ray spectroscopy. The electronic mid-IR intraband transition of the cation-exchanged self-doped quantum dots is further confirmed by measuring the infrared photocurrent spectrum of the QD-based infrared sensor.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"45 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144516226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

d-Electron Heavy Fermion Behavior in a Near-Room-Temperature Polar Metallic Ferrimagnet: A Case of Mn5SiC 近室温极性金属铁磁体中的d电子重费米子行为：以Mn5SiC为例

IF 8.6 2区材料科学

Chemistry of Materials Pub Date : 2025-06-25 DOI: 10.1021/acs.chemmater.5c00868

Zachary T. Messegee, Vasile Ovidiu Garlea, Igor I. Mazin, Seung Han Shin, Yan Xin, Hari Bhandari, Stuart Calder, Resham Babu Regmi, Nirmal J. Ghimire, Joon I. Jang, Xiaoyan Tan

{"title":"d-Electron Heavy Fermion Behavior in a Near-Room-Temperature Polar Metallic Ferrimagnet: A Case of Mn5SiC","authors":"Zachary T. Messegee, Vasile Ovidiu Garlea, Igor I. Mazin, Seung Han Shin, Yan Xin, Hari Bhandari, Stuart Calder, Resham Babu Regmi, Nirmal J. Ghimire, Joon I. Jang, Xiaoyan Tan","doi":"10.1021/acs.chemmater.5c00868","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c00868","url":null,"abstract":"Polycrystalline Mn5SiC was synthesized by using a high-temperature solid-state method. Mn5SiC adopts a polar space group (Cmc21) with six crystallographic Mn sites confirmed by X-ray and neutron diffraction, transmission electron microscopy, and second harmonic generation experiments. The complex crystal structure features edge-sharing trigonal prisms and icosahedra, as well as face/edge-sharing pentagonal prisms. Magnetic measurements indicate ferrimagnetic ordering with a transition temperature of 284 K. The ferrimagnetic structure (magnetic space group Cm’c’21) was further identified by powder neutron diffraction, where collinear Mn spins align along the crystallographic c-axis. The refined magnetic moment for each crystallographic Mn site at 4 K is 1.8(2), −2.42(9), −1.72(8), 0.51(6), 0.50(4), and 1.7(2) μB. Density functional theory calculations confirm both the metallic behavior and the ferrimagnetic structure observed experimentally and further provide insight into the observed Mn moment dependence across crystallographic sites. The resistivity and specific heat measurements and density functional theory calculations reveal a substantially large Kadowaki–Woods ratio of 5 × 10–5 μΩ·cm/(mJ/mol)2 and a many-body renormalization factor of 5.5, indicating the unusual heavy Fermion behavior in such an itinerant magnetic metal.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"12 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144516227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

IF 7.2 2区材料科学