The Hall coefficient in the low-temperature tetragonal phase and the
mid-temperature orthorhombic phase of La1.88−yYySr0.12CuO4
(y=0,0.04) single crystals is measured under high magnetic fields up to 9 T
in order to investigate the detailed behavior of the transport properties at
low temperatures in the stripe phase. When the superconductivity is suppressed
by high magnetic fields, the Hall coefficient has negative values in low
temperatures, and the temperature region of the negative values spreads as
increasing magnetic fields. This result indicates that the Hall coefficient in
the stripe phase around x=0.12 is a finite negative value, not zero.Comment: 4 pages, 4 figures. to be published to Physical Review