Effects of carrier doping on the quantum transport phenomena in organic massless Dirac electron system

2017 Fiscal Year Final Research Report

• Project/Area Number: 25287089
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Toho University
• Principal Investigator: TAJIMA Naoya 東邦大学, 理学部, 教授 (40316930)
• Co-Investigator(Kenkyū-buntansha): 西尾 豊 東邦大学, 理学部, 教授 (20172629) ; 森成 隆夫 京都大学, 人間・環境学研究科, 准教授 (70314284) ; 須田 理行 分子科学研究所, 協奏分子システム研究センター, 助教 (80585159)
• Project Period (FY): 2013-04-01 – 2018-03-31
• Keywords: 有機導体 / ディラック電子 / 量子ホール効果 / ランダウ準位

Outline of Final Research Achievements

We have discovered an organic conductor which 2D massless Dirac electron system was realized under high pressure. This is the first bulk massless Dirac electrons system. Moreover, according to the band calculation, the Dirac cones of this system are highly tilted. Thus, this material belongs to a broader category of 2D massless Dirac electrons system. However, both Shubnikov-de Haas (SdH) oscillations and quantum Hall effect (QHE) have not been observed yet in this system, because the Fermi level is always located at the Dirac point. Thus, the relativistic Landau levels has not directly been obtained yet. In this work, we succeeded in injecting carriers into this system. Significant is that SdH oscillations whose phase was modified by π Berry’s phase and half integer QHE were detected at low temperature. The detail examination of this quantum phenomena led to the reconstruction of the Dirac cones. Moreover, the tilt parameters of the Dirac cone were determined.

Free Research Field

固体物理学