  We studied the electronic structures of LaOFeP under applied pressure using
first-principles calculations. The electronic density of states at the Fermi
level decreases continuously with increasing pressure. The electron branches of
Fermi surfaces are rather robust to pressure, while the hole branches change
significantly. Two hole surfaces shrink into small ellipsoid-like surfaces and
disappear finally, at which the applied pressure is ~ 74.7 GPa. The pressure
response can be understood by the band structures around the Fermi level.
Comparative studies reveal that the disappearance of hole surfaces is mainly
due to the compression of the FeP layer along the c-axis of unit cell.
