Large edge magnetism in oxidized few-layer black phosphorus nanomeshes

The formation and control of a room-temperature magnetic order in two-dimensional (2D) materials is a challenging quest for the advent of innovative magnetic- and spintronic-based technologies. To date, edge magnetism in 2D materials has been experimentally observed in hydrogen (H)-terminated graphene nanoribbons (GNRs) and graphene nanomeshes (GNMs), but the measured magnetization remains far too small to allow envisioning practical applications. Herein, we report experimental evidences of large room-temperature edge ferromagnetism (FM) obtained from oxygen (O)-terminated zigzag pore edges of few-layer black phosphorus (P) nanomeshes (BPNMs). The magnetization values per unit area are ~100 times larger than those reported for H-terminated GNMs, while the magnetism is absent for H-terminated BPNMs. The magnetization measurements and the first-principles simulations suggest that the origin of such a magnetic order could stem from ferromagnetic spin coupling between edge P with O atoms, resulting in a strong spin localization at the edge valence band, and from uniform oxidation of full pore edges over a large area and interlayer spin interaction. Our findings pave the way for realizing high-efficiency 2D flexible magnetic and spintronic devices without the use of rare magnetic elements

Pb/Ru/Sr2RuO4接合におけるトポロジカルな超伝導干渉効果

京都大学0048新制・課程博士博士(理学)甲第16600号理博第3712号新制||理||1538(附属図書館)29275京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)教授 前野 悦輝, 教授 寺嶋 孝仁, 教授 石田 憲二学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA

Spontaneous superconducting diode effect in non-magnetic Nb/Ru/Sr2RuO4 topological junctions

Acknowledgements: We are grateful to B. Zinkl and G. Mattoni for helpful discussion. We acknowledge the support from International Center for Materials Nanoarchitectonics (MANA) in the National Institute for Materials Science (NIMS), Japan. This work is supported by JSPS KAKENHI (Nos. JP15H05852, JP15K21717, JP22H01168, JP23K17670, JP22H04473 and JP26287078), JSPS-EPSRC Core-to-Core Programme (No. JPJSCCA20170002), and the Swiss National Science Foundation (SNSF) through Division II (No. 184739). M.S.A. and J.W.A.R. acknowledges funding from the EPSRC International Network Grant “Oxide Superspin” (No. EP/P026311/1).AbstractNon-reciprocal electronic transport in a material occurs if both time reversal and inversion symmetries are broken. The superconducting diode effect (SDE) is an exotic manifestation of this type of behavior where the critical current for positive and negative currents are mismatched, as recently observed in some non-centrosymmetric superconductors with a magnetic field. Here, we demonstrate a SDE in non-magnetic Nb/Ru/Sr2RuO4 Josephson junctions without applying an external magnetic field. The cooling history dependence of the SDE suggests that time-reversal symmetry is intrinsically broken by the superconducting phase of Sr2RuO4. Applied magnetic fields modify the SDE dynamically by randomly changing the sign of the non-reciprocity. We propose a model for such a topological junction with a conventional superconductor surrounded by a chiral superconductor with broken time reversal symmetry.</jats:p

Spontaneous superconducting diode effect in nonmagnetic Nb/Ru/Sr2RuO4 topological junctions

Non-reciprocal electronic transport in a material occurs if both time reversal and inversion symmetries are broken. The superconducting diode effect (SDE) is an exotic manifestation of this type of behavior where the critical current for positive and negative currents are mismatched, as recently observed in some non-centrosymmetric superconductors with a magnetic field. Here, we demonstrate a SDE in non-magnetic Nb/Ru/Sr2RuO4 Josephson junctions without applying an external magnetic field. The cooling history dependence of the SDE suggests that time-reversal symmetry is intrinsically broken by the superconducting phase of Sr2RuO4. Applied magnetic fields modify the SDE dynamically by randomly changing the sign of the non-reciprocity. We propose a model for such a topological junction with a conventional superconductor surrounded by a chiral superconductor with broken time reversal symmetry.ISSN:2399-365

Spontaneous superconducting diode effect in non-magnetic Nb/Ru/Sr 2 RuO 4 topological junctions

Acknowledgements: We are grateful to B. Zinkl and G. Mattoni for helpful discussion. We acknowledge the support from International Center for Materials Nanoarchitectonics (MANA) in the National Institute for Materials Science (NIMS), Japan. This work is supported by JSPS KAKENHI (Nos. JP15H05852, JP15K21717, JP22H01168, JP23K17670, JP22H04473 and JP26287078), JSPS-EPSRC Core-to-Core Programme (No. JPJSCCA20170002), and the Swiss National Science Foundation (SNSF) through Division II (No. 184739). M.S.A. and J.W.A.R. acknowledges funding from the EPSRC International Network Grant “Oxide Superspin” (No. EP/P026311/1).Non-reciprocal electronic transport in a material occurs if both time reversal and inversion symmetries are broken. The superconducting diode effect (SDE) is an exotic manifestation of this type of behavior where the critical current for positive and negative currents are mismatched, as recently observed in some non-centrosymmetric superconductors with a magnetic field. Here, we demonstrate a SDE in non-magnetic Nb/Ru/Sr2RuO4 Josephson junctions without applying an external magnetic field. The cooling history dependence of the SDE suggests that time-reversal symmetry is intrinsically broken by the superconducting phase of Sr2RuO4. Applied magnetic fields modify the SDE dynamically by randomly changing the sign of the non-reciprocity. We propose a model for such a topological junction with a conventional superconductor surrounded by a chiral superconductor with broken time reversal symmetry