Schulze-Wischeler F, Hohls F, Zeitler U, Reuter D, Wieck A D, Haug R J
Institut für Festkörperphysik, Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany.
Phys Rev Lett. 2004 Jul 9;93(2):026801. doi: 10.1103/PhysRevLett.93.026801. Epub 2004 Jul 7.
Phonon excitations of fractional quantum Hall states at filling factors nu = 1/3, 2/5, 4/7, 3/5, 4/3, and 5/3 are experimentally shown to be based on Landau-level transitions of composite fermions. At filling factor nu = 2/3, however, a linear field dependence of the excitation energy in the high-field regime rather hints towards a spin transition excited by the phonons. We propose to explain this surprising observation by an only partially polarized 2/3 ground state, making the energetically lower lying spin transition also allowed for phonon excitations.
实验表明，在填充因子ν = 1/3、2/5、4/7、3/5、4/3和5/3时，分数量子霍尔态的声子激发基于复合费米子的朗道能级跃迁。然而，在填充因子ν = 2/3时，高场 regime中激发能量的线性场依赖性反而暗示了由声子激发的自旋跃迁。我们建议通过仅部分极化的2/3基态来解释这一惊人的观察结果，使得能量较低的自旋跃迁也能被声子激发所允许。
