Scanning tunneling spectroscopy on La2-xSrxCuO4 under magnetic field

Low temperature scanning tunneling microscopy and spectroscopy measurements have been performed on the optimally doped La1.85Sr0.15CuO4 (LSCO) single crystal at 4.2 K in a magnetic field of 6 T applied along the c axis. The spatial distribution of the local density of sates (LDOS) has been successfully obtained on the ab plane. Although the weak distribution of the zero-bias conductance has been observed, the significant change in LDOS originating from the vortex core states has not been observed within our resolution. This result suggests that the vortex core state is rather small in LSCO.