Topological superfluids are recently discovered quantum matters that host topologically protected gapless edge states known as Majorana fermions – exotic quantum particles that act as their own anti-particles and obey nontrivial non-Abelian statistics.Their realizations are widely believed to lie at the heart of future technologies such as fault-tolerant quantum computation.To date,the most efficient scheme to create topological superfluids is based on the model proposed by Sau,Lutchyn,Tewari and Das Sarma(SLTD)in 2010,where the topological transition is driven by an out-of-plane Zeeman field perpendicular to the plane of spin-orbit coupling.The resulting topological superfluid is gapped in the bulk,behaving similar to the well-known p-wave superfluid.In this talk,we report a new scheme by using in-plane Zeeman field,in a cold-atom setup of ultracold atomic Fermi gases.This leads to the discovery of a novel exotic topological superfluid,which has a number of unique features that are absent in the standard SLTD topological superfluids or p-wave superfluids.These include the spatially inhomogeneous(Fulde-Ferrell)pairing order parameter,gapless excitations in the bulk,and uni-directed Majorana surface states at the edges.This conceptually new exotic state of matter may shed lights on designing gapless topological materials in solid-state systems.