Wang L, Chepiga N, Ki D-K, Li L, Li F, Zhu W, Kato Y, Ovchinnikova O S, Mila F, Martin I, Mandrus D, Morpurgo A F
Department of Quantum Matter Physics and Group of Applied Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland.
Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
Phys Rev Lett. 2017 Jun 23;118(25):257203. doi: 10.1103/PhysRevLett.118.257203.
We investigate manifestations of topological order in monoaxial helimagnet Cr_{1/3}NbS_{2} by performing transport measurements on ultrathin crystals. Upon sweeping the magnetic field perpendicularly to the helical axis, crystals thicker than one helix pitch (48 nm) but much thinner than the magnetic domain size (∼1 μm) are found to exhibit sharp and hysteretic resistance jumps. We show that these phenomena originate from transitions between topological sectors with a different number of magnetic solitons. This is confirmed by measurements on crystals thinner than 48 nm-in which the topological sector cannot change-that do not exhibit any jump or hysteresis. Our results show the ability to deterministically control the topological sector of finite-size Cr_{1/3}NbS_{2} and to detect intersector transitions by transport measurements.
我们通过对超薄晶体进行输运测量，研究了单轴螺旋磁体Cr_{1/3}NbS_{2}中的拓扑序表现。在垂直于螺旋轴扫描磁场时，发现厚度大于一个螺旋节距（48纳米）但远小于磁畴尺寸（约1微米）的晶体表现出尖锐且具有滞后性的电阻跃变。我们表明，这些现象源于具有不同数量磁孤子的拓扑扇区之间的转变。对厚度小于48纳米的晶体进行的测量证实了这一点，在这种情况下拓扑扇区无法改变，晶体未表现出任何跃变或滞后现象。我们的结果表明，能够确定性地控制有限尺寸Cr_{1/3}NbS_{2}的拓扑扇区，并通过输运测量检测扇区间的转变。
