Abstract
Ground state of the two-dimensional hard-core-boson model subjected to external magnetic field and quenched random chemical potential is studied numerically. In experiments, magnetic-field-tuned superconductor-insulator transition has already come under through investigation, whereas in computer simulation, only randomness-driven localization (with zero magnetic field) has been studied so far: The external magnetic field brings about a difficulty that the hopping amplitude becomes complex number (through the gauge twist), for which the quantum Monte-Carlo simulation fails. Here, we employ the exact diagonalization method, with which we demonstrate that the model does exhibit field-tuned localization transition at a certain critical magnetic field. At the critical point, we found that the DC conductivity is not universal, but is substantially larger than that of the randomness-driven localization transition at zero magnetic field. Our result supports recent experiment by Marković et al. reporting an increase of the critical conductivity with magnetic field strengthened.
Original language | English |
---|---|
Pages (from-to) | 147-155 |
Number of pages | 9 |
Journal | Physica C: Superconductivity and its applications |
Volume | 353 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - May 1 2001 |
Keywords
- Critical conductivity
- Dynamical critical exponent
- Exact-diagonalization method
- Finite-size-scaling method
- Randomness
- Superconductor-insulator transition
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering