We employ NMR techniques to investigate the nature of Mn spins in the I-II-V diluted magnetic semiconductor Li(Zn1−xMnx)P (x = 0.1, Curie temperature Tc = 25 K). We successfully identify the 7 Li NMR signals arising from the Li sites adjacent to Mn 2+ , and probe the static and dynamic properties of Mn spins. From the NMR spin-lattice relaxation data, we show that the Mn spin-spin interactions extend over many unit cells.

No abstract

We employ NMR techniques to investigate the nature of Mn spins in the I-II-V diluted magnetic semiconductor Li(Zn1−xMnx)P (x = 0.1, Curie temperature Tc = 25 K). We successfully identify the 7 Li NMR signals arising from the Li sites adjacent to Mn 2+ , and probe the static and dynamic properties of Mn spins. From the NMR spin-lattice relaxation data, we show that the Mn spin-spin interactions extend over many unit cells.

Recent emergence of two-dimensional (2D) crystalline superconductors has provided a promising platform to investigate novel quantum physics and potential applications. To reveal essential quantum phenomena therein, ultralow temperature transport investigation on high-quality ultrathin superconducting films is critically required, although it has been quite challenging experimentally. Here, we report a systematic transport study on the ultrathin crystalline PdTe 2 films grown by molecular beam epitaxy (MBE). Interestingly, a new type of Ising superconductivity in 2D centrosymmetric materials is revealed by the detection of large inplane critical field more than 7 times the Pauli limit. Remarkably, in a perpendicular magnetic field, we provide solid evidence of an anomalous metallic state characterized by the resistance saturation at low temperatures with high-quality filters. The robust superconductivity with intriguing quantum phenomena in the macro-size ambient-stable ultrathin PdTe 2 films remains almost the same for 20 months, showing great potentials in electronic and spintronic applications.

No abstract

We use muon spin relaxation (μSR) to investigate the magnetic properties of a bulk form diluted ferromagnetic semiconductor (DFS) Li 1.15 (Zn 0.9 Mn 0.1)P with T C ∼ 22 K. μSR results confirm the gradual development of ferromagnetic ordering below T C with a nearly 100% magnetic ordered volume. Despite its low carrier density, the relation between static internal field and Curie temperature observed for Li(Zn,Mn)P is consistent with the trend found in (Ga,Mn)As and other bulk DFSs, indicating these systems share a common mechanism for the ferromagnetic exchange interaction. Li 1+y (Zn 1−x Mn x)P has the advantage of decoupled carrier and spin doping, where Mn 2+ substitution for Zn 2+ introduces spins and Li + off-stoichiometry provides carriers. This advantage enables us to investigate the influence of overdoped Li on the ferromagnetic ordered state. Overdoping Li suppresses both T C and saturation moments for a certain amount of spins, which indicates that more carriers are detrimental to the ferromagnetic exchange interaction, and that a delicate balance between charge and spin densities is required to achieve highest T C .

RENiO3 (RE=rare-earth element) and V2O3 are archetypal Mott insulator systems. When tuned by chemical substitution (RENiO3) or pressure (V2O3), they exhibit a quantum phase transition (QPT) between an antiferromagnetic Mott insulating state and a paramagnetic metallic state. Because novel physics often appears near a Mott QPT, the details of this transition, such as whether it is first or second order, are important. Here, we demonstrate through muon spin relaxation/rotation (μSR) experiments that the QPT in RENiO3 and V2O3 is first order: the magnetically ordered volume fraction decreases to zero at the QPT, resulting in a broad region of intrinsic phase separation, while the ordered magnetic moment retains its full value until it is suddenly destroyed at the QPT. These findings bring to light a surprising universality of the pressure-driven Mott transition, revealing the importance of phase separation and calling for further investigation into the nature of quantum fluctuations underlying the transition.

No abstract