Micro wave dependence of the tunneling current in the bilayer quantum Hall system at the total filling v=1

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540319
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Kyoto University
• Principal Investigator: SAWADA Anju 京都大学, 低温物質科学研究センター, 名誉教授 (90115577)
• Co-Investigator(Kenkyū-buntansha): EZAWA Jyunichi 理化学研究所, 岩崎先端中間子研究室, 客員研究員 (90133925)
• Co-Investigator(Renkei-kenkyūsha): ARAI Toshikazu 東北工業大学, 共通教育センター, 准教授 (80333318) ; FUKUDA Akira 兵庫医科大学, 医学部, 准教授 (70360633)
• Research Collaborator: TSUDA Shibun ; MITANI Shohei
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 量子ホール効果 / 複合ボソン / ボース凝縮 / 巨視的コヒーレンス / ジョセフソン効果 / 分数量子ホール効果 / 抵抗増大現象

Outline of Final Research Achievements

We investigate Josephson tunneling in the bilayer quantum Hall system at the total filling ν = 1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless. Our results explain recent experiments.
We were going to experiment on the AC Josephson effect, but the sample was defective, and we had to prepare a new sample. During this time, we went ahead with a study of the huge longitudinal resistance (HLR) state by increasing the electric current at the filling ν = 2/3 quantum Hall state. We obtained the following new experimental results: 1) the HLR state exhibits the negative temperature dependence; 2) the HLR state is formed by AC current, not by DC current; 3) the Hall resistance retains the plateau shape even in the HLR state; and 4) the Hall resistance value shifts depending on the filling value position of the current pumping. We construct a new model of the HLR state by using the new experimental results.

Free Research Field

半導体物理学