Theoretical Study of Magnetic-Field-Induced Anomalous Quantum Phenomena of Frustrated Magnets by Large-Scale Parallel Calculations

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540348
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: University of Hyogo
• Principal Investigator: NAKANO Hiroki 兵庫県立大学, 物質理学研究科, 助教 (00343418)
• Co-Investigator(Kenkyū-buntansha): TODOROKI Norikazu 千葉工業大学, 工学部, 准教授 (40409925)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 量子スピン系 / ハイゼンベルク反強磁性体 / 厳密対角化法 / 大規模並列計算

Outline of Final Research Achievements

This project studies anomalous quantum phenomena of frustrated magnets appearing in magnetic fields by the numerically exact diagonalization method. As a typical case of such magnets in two dimensions, the Heisenberg antiferromagnet on the kagome lattice has long been studied; however, our understanging of this system is still far from the completeness. An open issue is that, although the systems show a small-gradient region of the magnetic field at one-third height of the saturation in their magnetization processes, the behavior is different from well-known magnetic plateaux. By the large-scale parallel calculations in supercomputers including K computer, we have clarified the fact that the case at this height is just on the boundary between two different phases when the system is distorted. We thus pointed out that the anomalous behavior is related to the fact of the phase boundary. We also found in one of the two phases that a magnetization jump owing to the spin-flop phenomenon.

Free Research Field

物性理論