Pressure-Quenched Superconductivity in Weyl Semimetal NbP Induced by Electronic Phase Transitions under Pressure

Abstract

The TaAs family (NbAs, TaAs, NbP, TaP) are kinds of Weyl semimetals with lots of novel properties, thus attracting considerable attention in recent years. Here, we systematically studied the Weyl semimetal NbP up to 72 GPa through the resistivity, Raman spectra, X-ray diffraction measurements, and first-principles density functional theory (DFT) calculations. A pressure-induced semimetal−metal transition was observed at ∼36 GPa, which was further confirmed by the DFT calculations. With further compression up to 52 GPa, a superconducting state was observed. Interestingly, the T c increases significantly upon decompression and shows a dome-shaped trend as a function of pressure. Surprisingly, the pressure-induced superconductivity can be quenched to ambient pressure, and all transitions under pressure do not involve any structural change. Our work not only depicts a phase diagram of the NbP system under high pressure but also provides a new experimental insight for superconductivity in Weyl semimetals.

Superconductivity Induced by Lifshitz Transition in Pristine SnS2 under High Pressure

“…In the decompression run, the R – T curve gradually degrades into semiconductor behavior, but the T c is enhanced to 5.1 K when the pressure is released to 52.6 GPa, as shown in the Figure S2. The decompression-enhanced or persistent superconductivity has also been reported on some other chalcogenides or pnictides, which is attributed to the irreversibility in grain and structure of pressurized crystals. − For the second run, superconductivity with T c = 3.1 K emerges at 43.7 GPa, and the T c is enhanced to 6.2 K at 82.7 GPa, as shown in Figure c. The temperature dependence of the upper critical field at 70.5 and 82.7 GPa are depicted in Figure d.…”

Rewritable Pressure-Driven n–p Conduction Switching in Marcasite-Type CrSb2

“…The softening of A g and B 2g modes here may imply the structural instability of [CrSb 6 ] octahedra with an increasing degree of distortion under pressure. In addition, the full width at half-maximum (FWHM) of the two modes significantly increases at 3.0 GPa, indicating that the electron–phonon coupling changes . Since HP XRD data shows no structural phase transition around 3 GPa, the changes in linewidths are most likely related to electronic transitions in isomorphic structures, such as Lifshitz transition, as reported in NbAs 2 .…”

“…In addition, the full width at half-maximum (FWHM) of the two modes significantly increases at 3.0 GPa, indicating that the electron−phonon coupling changes. 55 Since HP XRD data shows no structural phase transition around 3 GPa, the changes in linewidths are most likely related to electronic transitions in isomorphic structures, such as Lifshitz transition, as reported in NbAs 2 . 56 Corresponding to the pressure-induced structural phase transition from marcasite to arsenopyrite, the intensity of Raman peaks vanishes at 11.6 GPa, indicating that the sample may exhibit a metallic behavior with compression.…”

Pressure-induced disorder and nanosizing inhibits superconductivity in In2Te3

“…For example, the formation of superconducting islands on the insulating side of SIT has been observed [9]. Pressure-quenched superconductivity induced by electronic phase transitions under pressure in Weyl semimetal NbP was reported in previous work [10]. In addition, investigations on the electronic structural transition of chalcogenides, the reversibility of transition, the relevance of hydrostatic pressure and phase transition related to superconductivity were also explored [11][12][13].…”