Density wave states in the presence of an external magnetic field

Article

关键词: BLOCH ELECTRONS;    DIAMAGNETISM;    SPECTRUM;   

DOI  :  10.1103/PhysRevB.100.075150

来源: SCIE

【 摘 要 】

We investigate the effect that density wave states have on the Hofstadter butterfly. We first review the problem of the d-density wave on a square lattice and then numerically solve the d-density wave problem when an external magnetic field is introduced. As the d-density wave condensation strength is tuned the spectrum evolves through three topologically distinct butterflies, and a relativistic quantum Hall effect is observed. The chiral p + ip-density wave state demonstrates drastically different Hofstadter physics-inducing a destruction of the gaps in the butterfly which causes electrons' cyclotron orbits to not obey any type of Landau quantization, and the creation of a large gap in the spectrum with Hall conductance sigma(xy) = 0. To investigate the quantum phases in the system we perform a multifractal analysis of the single particle wave functions. We find that tuning the d-density wave strength at a generic value of magnetic flux controls a metal-metal transition at charge neutrality where the wave-function multifractality occurs at energy level crossings. In the p + ip case we observe another metal-metal transition occurring at an energy level crossing separated by a strongly multifractal quasi-insulating island state occurring at charge neutrality and strip dimerization of the lattice.

【 授权许可】

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