  We derived an analytic structure of the quark mass correction to chiral
separation effect (CSE) in small mass regime. We confirmed this structure by a
D3/D7 holographic model study in a finite density, finite magnetic field
background. The quark mass correction to CSE can be related to correlators of
pseudo-scalar condensate, quark number density and quark condensate in static
limit. We found scaling relations of these correlators with spatial momentum in
the small momentum regime. They characterize medium responses to electric
field, inhomogeneous quark mass and chiral shift. Beyond the small momentum
regime, we found existence of normalizable mode, which possibly leads to
formation of spiral phase. The normalizable mode exists beyond a critical
magnetic field, whose magnitude decreases with quark chemical potential.
