Achieving polarization switching in wurtzite(wz)crystals has long been hindered by substantial energy barriers and high coercive electric fields.Here,we demonstrate that an in-plane ferroelectric(FE)switch can be trig...Achieving polarization switching in wurtzite(wz)crystals has long been hindered by substantial energy barriers and high coercive electric fields.Here,we demonstrate that an in-plane ferroelectric(FE)switch can be triggered within the(0001)crystallographic plane,through the discovery of hiddenAbm2 and Pmc2_(1)monolayer phases.The structural self-reconstruction,induced by lattice expansion,converts interfacial covalent bonds into van der Waals interactions,enabling facile exfoliation of wz monolayers.These monolayers exhibit multiferroic order and diverse electronic functionalities,including giant spin splittings(~540 meV),transition between half-metal and semiconductor,and wide band gaps(0–4.57 eV).Importantly,the FE transition can be finely tuned via a transient state,leading to significant reductions in the barrier energy(<~3 meV/atom)and coercive field(~0.6–1.0 MV/cm),and yielding fully electric control of 100%spin polarization.Our study provides in-depth insights into the inplane FE mechanism in wz systems,opening new avenues for the design and discovery of wz-based FE devices,as well as the rich physics in tetrahedral semiconductors.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12574067,61827815)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030086)+1 种基金Shenzhen Science and Technology Innovation Commission(Grant Nos.JCYJ20250529085144002,JCYJ20220531102601004,KOTD20180412181422399)Shenzhen University 2035 Program for Excellent Research(Grant No.2023C010).
文摘Achieving polarization switching in wurtzite(wz)crystals has long been hindered by substantial energy barriers and high coercive electric fields.Here,we demonstrate that an in-plane ferroelectric(FE)switch can be triggered within the(0001)crystallographic plane,through the discovery of hiddenAbm2 and Pmc2_(1)monolayer phases.The structural self-reconstruction,induced by lattice expansion,converts interfacial covalent bonds into van der Waals interactions,enabling facile exfoliation of wz monolayers.These monolayers exhibit multiferroic order and diverse electronic functionalities,including giant spin splittings(~540 meV),transition between half-metal and semiconductor,and wide band gaps(0–4.57 eV).Importantly,the FE transition can be finely tuned via a transient state,leading to significant reductions in the barrier energy(<~3 meV/atom)and coercive field(~0.6–1.0 MV/cm),and yielding fully electric control of 100%spin polarization.Our study provides in-depth insights into the inplane FE mechanism in wz systems,opening new avenues for the design and discovery of wz-based FE devices,as well as the rich physics in tetrahedral semiconductors.
