Pressure induced superconductivity in MnSe

Abstract

The rich phenomena in the FeSe and related compounds have attracted great interests as it provides fertile material to gain further insight into the mechanism of high temperature superconductivity. A natural follow-up work was to look into the possibility of superconductivity in MnSe. We demonstrated in this work that high pressure can effectively suppress the complex magnetic characters of MnSe, and induce superconductivity with Tc ~ 5 K at pressure ~12 GPa confirmed by both magnetic and resistive measurements. The highest Tc is ~ 9 K (magnetic result) at ~35 GPa. Our observations suggest the observed superconductivity may closely relate to the pressure-induced structural change. However, the interface between the metallic and insulating boundaries may also play an important role to the pressure induced superconductivity in MnSe.

Investigations of Structural, Electronic and Magnetic Properties of MnSe under High Pressure

“…Furthermore, high-pressure properties of manganese chalcogenides, such as MnSe and MnS 2 , have also attracted attention, since they exhibit large cell volume collapse and spin crossover during pressure-induced phase transitions [ 9 , 10 , 11 ]. Interestingly, a recent study reported the observation of superconductivity with T C ~ 9 K in pressurized MnSe at ~35 GPa [ 12 ]. However, the superconducting structure is not clear yet.…”

“…However, the same transition was observed at 140 K during the cooling process performed by means of synchrotron X-ray and neutron diffraction [ 14 ]. Furthermore, experimental works based on the in situ synchrotron XRD pattern [ 12 ] and the in situ angle dispersive synchrotron X-ray diffraction pattern [ 9 ] demonstrated that at room temperature, the low-pressure (LP) (0~12 GPa) and high-pressure (HP) (>30 GPa) phase structures of MnSe are NaCl-type with Fm-3m symmetry and MnP-type with Pnma symmetry, respectively. However, in [ 9 ], it is pointed out that there is an unknown tetrahedral structure between the Fm-3m and Pnma phases.…”

“…However, in [ 9 ], it is pointed out that there is an unknown tetrahedral structure between the Fm-3m and Pnma phases. The study also indicates the coexistence of the Fm-3m and P6 3 /mmc phases between 12.2 GPa and 16 GPa and the coexistence of the Fm-3m, P6 3 /mmc and Pnma phases between 16 GPa and 30 GPa [ 12 ]. On the other hand, the existing theoretical works [ 15 , 16 ] mainly studied the electronic structures of the Fm-3m phase, and there is a lack of reports on the structural evolution of MnSe under high pressure.…”

“…On the other hand, the existing theoretical works [ 15 , 16 ] mainly studied the electronic structures of the Fm-3m phase, and there is a lack of reports on the structural evolution of MnSe under high pressure. We found that although lots of works had been conducted to explore the structures of MnSe, the evolution of the structure with pressure has not been clarified yet, especially the mixed phases between the Fm-3m phase and the Pnma phase observed by the experiment [ 9 , 12 ].…”

“…Furthermore, theoretical [ 10 ] and experimental [ 9 , 12 ] results suggested that the spin state transition, metal–insulator transition and superconductivity can be found in pressurized MnSe, but the superconducting mechanism has not yet been elucidated. Studying the evolution of magnetic moments and structures with pressure can give assistance to gain further insight into the mechanism of superconductivity in MnSe.…”