Research of the dynamic Kosterlitz-Thouless phase transition in bilayer quantum Hall states

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540331
• 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: Hyogo Medical University
• Principal Investigator: FUKUDA Akira 兵庫医科大学, 医学部, 准教授 (70360633)
• Co-Investigator(Kenkyū-buntansha): TERASAWA Daiju 兵庫医科大学, 医学部, 助教 (90589839)
• Co-Investigator(Renkei-kenkyūsha): SAWADA Anju 京都大学, 低温物質科学研究センター, 教授 (90115577) ; EZAWA Junichi 独立行政法人理化学研究所, 客員研究員 (90133925)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 量子ホール効果 / ２層系 / K-T転移 / 擬スピン / 半量子渦対 / グラフェン

Outline of Final Research Achievements

Bilayer ν=1 quantum Hall state (QHS) is discribed by the X-Y model of pseudospins with macroscopic quantum coherence. Kosterlitz-Thouless (K-T) phase transition is expected to occur by the dissociation and recombination of half-quantized vorticies. In this study, we observe the onset temperature TC of QHS in the bilayer ν=1 QHS using high-mobility GaAs semiconductor samples. Results indicate that TC is significantly related to the K-T temperature. We also measure the relaxation time of nuclear spins in the bilayer ν=1 QHS by means of dynamic nuclear poralization in the ν=2/3 QHS. Consequently we indicate the existence of the SU(4) skyrmions.

Free Research Field

低温・半導体物理学