Due to the upcoming demands of next-generation electronic/magnetoelectronic devices with low-energy consumption,emerging correlated materials（such as superconductors,topological insulators and manganites） are one of...Due to the upcoming demands of next-generation electronic/magnetoelectronic devices with low-energy consumption,emerging correlated materials（such as superconductors,topological insulators and manganites） are one of the highly promising candidates for the applications.For the past decades,manganites have attracted great interest due to the colossal magnetoresistance effect,charge-spin-orbital ordering,and electronic phase separation.However,the incapable of deterministic control of those emerging low-dimensional spin structures at ambient condition restrict their possible applications.Therefore,the understanding and control of the dynamic behaviors of spin order parameters at nanoscale in manganites under external stimuli with low energy consumption,especially at room temperature is highly desired.In this review,we collected recent major progresses of nanoscale control of spin structures in manganites at low dimension,especially focusing on the control of their phase boundaries,domain walls as well as the topological spin structures（e.g.,skyrmions）.In addition,capacitor-based prototype spintronic devices are proposed by taking advantage of the above control methods in manganites.This capacitor-based structure may provide a new platform for the design of future spintronic devices with low-energy consumption.展开更多
We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO3（111） substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have...We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO3（111） substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have identified intriguing extra bump/dip features from anomalous Hall experiments on the films with thicknesses less than 12 nm. This observed Hall anomaly is phenomenologically consistent with the occurrence of a topological Hall effect （THE） in chiral magnets with a skyrmion phase. Furthermore, the THE contribution can be tuned by the film thickness, showing the key contribution of asymmetric interfaces in stabilizing N6el-type skyrmions. Our work demonstrates that a CrTe thin film on SrTiO3（111） substrates is a good material candidate for studying real-space topological transport.展开更多
The study of non-Hermitian systems with parity-time(PT)symmetry is a rapidly developing frontier in recent years?Experimentally,PT-symmetric systems have been realized in classical optics by balancing gain and loss,wh...The study of non-Hermitian systems with parity-time(PT)symmetry is a rapidly developing frontier in recent years?Experimentally,PT-symmetric systems have been realized in classical optics by balancing gain and loss,which holds great promise for novel optical devices and networks?Here we report experimental realization of passive PT-symmetric quantum dynamics for single photons by temporally alternating photon losses in the quantum walk(QW)interferometers.The ability to impose PT symmetry allows us to realize and investigate Floquet topological phases driven by PT-symmetric QWs.We observe topological edge states between regions with different topological invariants?Topological invariants can be defined by winding numbers,Zak phases,general geometry phases and can be calculated?Can they be detected directly?We give an answer by reporting the experimental detection of bulk topological invariants in non-unitary QWs?The topological invariant of the non-unitary quantum walk is manifested in the quantized average displacement of the walker,which is probed by monitoring the photon loss.Furthermore,we report the experimental study of dynamic quantum phase transitions(DQPTs)and photonic skyrmions using discrete-time QWs?We simulate quench dynamics between distinct Floquet topological phases using quantum-walk dynamics,and experimentally characterize DQPTs and emergent skyrmion structures.Our results pave the way for realizing quantum mechanical PT-synthetic devices and augurs exciting possibilities for exploring topological properties of non-Hermitian systems using discretetime QWs.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2014CB920902)the National Natural Science Foundation of China(Grant Nos.61306105 and 51572278)+1 种基金the Information Science and Technology(TNList)Cross-discipline Foundation from Tsinghua National Laboratory,Chinathe Fund from the State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China
文摘Due to the upcoming demands of next-generation electronic/magnetoelectronic devices with low-energy consumption,emerging correlated materials（such as superconductors,topological insulators and manganites） are one of the highly promising candidates for the applications.For the past decades,manganites have attracted great interest due to the colossal magnetoresistance effect,charge-spin-orbital ordering,and electronic phase separation.However,the incapable of deterministic control of those emerging low-dimensional spin structures at ambient condition restrict their possible applications.Therefore,the understanding and control of the dynamic behaviors of spin order parameters at nanoscale in manganites under external stimuli with low energy consumption,especially at room temperature is highly desired.In this review,we collected recent major progresses of nanoscale control of spin structures in manganites at low dimension,especially focusing on the control of their phase boundaries,domain walls as well as the topological spin structures（e.g.,skyrmions）.In addition,capacitor-based prototype spintronic devices are proposed by taking advantage of the above control methods in manganites.This capacitor-based structure may provide a new platform for the design of future spintronic devices with low-energy consumption.
文摘We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO3（111） substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have identified intriguing extra bump/dip features from anomalous Hall experiments on the films with thicknesses less than 12 nm. This observed Hall anomaly is phenomenologically consistent with the occurrence of a topological Hall effect （THE） in chiral magnets with a skyrmion phase. Furthermore, the THE contribution can be tuned by the film thickness, showing the key contribution of asymmetric interfaces in stabilizing N6el-type skyrmions. Our work demonstrates that a CrTe thin film on SrTiO3（111） substrates is a good material candidate for studying real-space topological transport.
基金supported by the National Natural Science Foundation of China(Grant Nos.11674056 and U1930402)the Natural Science Foundation of Jiangsu Province(Grant No.BK20160024)the startup funding of Beijing Computational Science Research Center
文摘The study of non-Hermitian systems with parity-time(PT)symmetry is a rapidly developing frontier in recent years?Experimentally,PT-symmetric systems have been realized in classical optics by balancing gain and loss,which holds great promise for novel optical devices and networks?Here we report experimental realization of passive PT-symmetric quantum dynamics for single photons by temporally alternating photon losses in the quantum walk(QW)interferometers.The ability to impose PT symmetry allows us to realize and investigate Floquet topological phases driven by PT-symmetric QWs.We observe topological edge states between regions with different topological invariants?Topological invariants can be defined by winding numbers,Zak phases,general geometry phases and can be calculated?Can they be detected directly?We give an answer by reporting the experimental detection of bulk topological invariants in non-unitary QWs?The topological invariant of the non-unitary quantum walk is manifested in the quantized average displacement of the walker,which is probed by monitoring the photon loss.Furthermore,we report the experimental study of dynamic quantum phase transitions(DQPTs)and photonic skyrmions using discrete-time QWs?We simulate quench dynamics between distinct Floquet topological phases using quantum-walk dynamics,and experimentally characterize DQPTs and emergent skyrmion structures.Our results pave the way for realizing quantum mechanical PT-synthetic devices and augurs exciting possibilities for exploring topological properties of non-Hermitian systems using discretetime QWs.
