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Superconductivity emerging from a suppressed large magnetoresistant state in tungsten ditelluride.

Kang D, Zhou Y, Yi W, Yang C, Guo J, Shi Y, Zhang S, Wang Z, Zhang C, Jiang S, Li A, Yang K, Wu Q, Zhang G, Sun L, Zhao Z - Nat Commun (2015)

Bottom Line: The large magnetoresistance effect originates from a perfect balance of hole and electron carriers, which is sensitive to external pressure.Upon increasing pressure, the positive large magnetoresistance effect is gradually suppressed and turned off at a critical pressure of 10.5 GPa, where superconductivity accordingly emerges.In situ high-pressure Hall coefficient measurements at low temperatures demonstrate that elevating pressure decreases the population of hole carriers but increases that of the electron ones.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.

ABSTRACT
The recent discovery of large magnetoresistance in tungsten ditelluride provides a unique playground to find new phenomena and significant perspective for potential applications. The large magnetoresistance effect originates from a perfect balance of hole and electron carriers, which is sensitive to external pressure. Here we report the suppression of the large magnetoresistance and emergence of superconductivity in pressurized tungsten ditelluride via high-pressure synchrotron X-ray diffraction, electrical resistance, magnetoresistance and alternating current magnetic susceptibility measurements. Upon increasing pressure, the positive large magnetoresistance effect is gradually suppressed and turned off at a critical pressure of 10.5 GPa, where superconductivity accordingly emerges. No structural phase transition is observed under the pressure investigated. In situ high-pressure Hall coefficient measurements at low temperatures demonstrate that elevating pressure decreases the population of hole carriers but increases that of the electron ones. Significantly, at the critical pressure, a sign change of the Hall coefficient is observed.

No MeSH data available.


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Pressure–temperature phase diagram of WTe2 and pressure-dependent Hall coefficient.(a) The T*ZF and Tc versus pressure. The red, pink and blue solid circles represent Tc extracted from different runs of electrical resistance measurements, and the green triangles represent the Tc determined from the a.c. susceptibility measurements. The acronyms LMR and SC stand for the large magnetoresistant state and superconducting state, respectively. The error bars represent the s.d. (b) Hall coefficient (RH) as a function of pressure measured at 10 K and 1 Tesla, displaying a sign change from the positive to the negative at the critical pressure of 10.5 GPa. Solid purple circles and pink squares represent the RH obtained from different runs. The inset shows the second derivative of the Hall coefficient, the maximum of which corresponds to the sign change of Hall coefficient. The shaded area indicates the pressure range where the superconductivity emerges and the sign of RH changes.
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f6: Pressure–temperature phase diagram of WTe2 and pressure-dependent Hall coefficient.(a) The T*ZF and Tc versus pressure. The red, pink and blue solid circles represent Tc extracted from different runs of electrical resistance measurements, and the green triangles represent the Tc determined from the a.c. susceptibility measurements. The acronyms LMR and SC stand for the large magnetoresistant state and superconducting state, respectively. The error bars represent the s.d. (b) Hall coefficient (RH) as a function of pressure measured at 10 K and 1 Tesla, displaying a sign change from the positive to the negative at the critical pressure of 10.5 GPa. Solid purple circles and pink squares represent the RH obtained from different runs. The inset shows the second derivative of the Hall coefficient, the maximum of which corresponds to the sign change of Hall coefficient. The shaded area indicates the pressure range where the superconductivity emerges and the sign of RH changes.

Mentions: A characteristic temperature (T*ZF) as the turn-on temperature of the LMR effect at zero field is defined, as indicated by the arrows in the inset of Fig. 3a. Such a definition of the T*ZF is coincident with the temperature of the linear extrapolation of turn-on LMR temperatures under different magnetic fields. Then we summarize our experimental results in the pressure–temperature phase diagram (Fig. 6a). There are two distinct regions in the diagram: the LMR state and the superconducting state. It is found that the T*ZF of the LMR state decreases with increasing pressure and vanishes at the critical pressure 10.5 GPa, where the superconductivity emerges at 2.8 K. The value of Tc increases up to a maximum at 13.0 GPa and then declines with further increasing pressure. This phase diagram clearly demonstrates how the pressure can effectively suppress the LMR state and induce superconductivity.


Superconductivity emerging from a suppressed large magnetoresistant state in tungsten ditelluride.

Kang D, Zhou Y, Yi W, Yang C, Guo J, Shi Y, Zhang S, Wang Z, Zhang C, Jiang S, Li A, Yang K, Wu Q, Zhang G, Sun L, Zhao Z - Nat Commun (2015)

Pressure–temperature phase diagram of WTe2 and pressure-dependent Hall coefficient.(a) The T*ZF and Tc versus pressure. The red, pink and blue solid circles represent Tc extracted from different runs of electrical resistance measurements, and the green triangles represent the Tc determined from the a.c. susceptibility measurements. The acronyms LMR and SC stand for the large magnetoresistant state and superconducting state, respectively. The error bars represent the s.d. (b) Hall coefficient (RH) as a function of pressure measured at 10 K and 1 Tesla, displaying a sign change from the positive to the negative at the critical pressure of 10.5 GPa. Solid purple circles and pink squares represent the RH obtained from different runs. The inset shows the second derivative of the Hall coefficient, the maximum of which corresponds to the sign change of Hall coefficient. The shaded area indicates the pressure range where the superconductivity emerges and the sign of RH changes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525168&req=5

f6: Pressure–temperature phase diagram of WTe2 and pressure-dependent Hall coefficient.(a) The T*ZF and Tc versus pressure. The red, pink and blue solid circles represent Tc extracted from different runs of electrical resistance measurements, and the green triangles represent the Tc determined from the a.c. susceptibility measurements. The acronyms LMR and SC stand for the large magnetoresistant state and superconducting state, respectively. The error bars represent the s.d. (b) Hall coefficient (RH) as a function of pressure measured at 10 K and 1 Tesla, displaying a sign change from the positive to the negative at the critical pressure of 10.5 GPa. Solid purple circles and pink squares represent the RH obtained from different runs. The inset shows the second derivative of the Hall coefficient, the maximum of which corresponds to the sign change of Hall coefficient. The shaded area indicates the pressure range where the superconductivity emerges and the sign of RH changes.
Mentions: A characteristic temperature (T*ZF) as the turn-on temperature of the LMR effect at zero field is defined, as indicated by the arrows in the inset of Fig. 3a. Such a definition of the T*ZF is coincident with the temperature of the linear extrapolation of turn-on LMR temperatures under different magnetic fields. Then we summarize our experimental results in the pressure–temperature phase diagram (Fig. 6a). There are two distinct regions in the diagram: the LMR state and the superconducting state. It is found that the T*ZF of the LMR state decreases with increasing pressure and vanishes at the critical pressure 10.5 GPa, where the superconductivity emerges at 2.8 K. The value of Tc increases up to a maximum at 13.0 GPa and then declines with further increasing pressure. This phase diagram clearly demonstrates how the pressure can effectively suppress the LMR state and induce superconductivity.

Bottom Line: The large magnetoresistance effect originates from a perfect balance of hole and electron carriers, which is sensitive to external pressure.Upon increasing pressure, the positive large magnetoresistance effect is gradually suppressed and turned off at a critical pressure of 10.5 GPa, where superconductivity accordingly emerges.In situ high-pressure Hall coefficient measurements at low temperatures demonstrate that elevating pressure decreases the population of hole carriers but increases that of the electron ones.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.

ABSTRACT
The recent discovery of large magnetoresistance in tungsten ditelluride provides a unique playground to find new phenomena and significant perspective for potential applications. The large magnetoresistance effect originates from a perfect balance of hole and electron carriers, which is sensitive to external pressure. Here we report the suppression of the large magnetoresistance and emergence of superconductivity in pressurized tungsten ditelluride via high-pressure synchrotron X-ray diffraction, electrical resistance, magnetoresistance and alternating current magnetic susceptibility measurements. Upon increasing pressure, the positive large magnetoresistance effect is gradually suppressed and turned off at a critical pressure of 10.5 GPa, where superconductivity accordingly emerges. No structural phase transition is observed under the pressure investigated. In situ high-pressure Hall coefficient measurements at low temperatures demonstrate that elevating pressure decreases the population of hole carriers but increases that of the electron ones. Significantly, at the critical pressure, a sign change of the Hall coefficient is observed.

No MeSH data available.


Related in: MedlinePlus