High Pressure and Road to Room Temperature Superconductivity

Abstract

High pressure serves as a path finding tool towards novel structures, including those with very high Tc.The superconductivity in sulfur hydrides with record value (203 K) is caused by the phonon mechanism. However, the picture differs from the conventional one in important ways. The phonon spectrum in sulfur hydride is both broad and has a complex structure. High value of Tc is mainly due to strong coupling to the high-frequency optical modes, although the acoustic phonons also make a noticeable contribution. New approach is described;it generalizes the standard treatment of the phonon mechanism and makes it possible to obtain an analytical expression for Tc . It turns out that, unlike in the conventional case, the value of the isotope coefficient varies with the pressure and reflects the impact of the optical modes. The phase diagram, that is the pressure dependence of Tc, is rather peculiar. A crucial feature is that increasing pressure results in a series of structural transitions, including the one, which yields the superconducting phase with the record Tc.In a narrow region near 150GPa the critical temperature rises sharply from 120K to 200K. The sharp structural transition, which produces the high Tc phase, is a first-order phase transition caused by interaction between the order parameter and lattice deformations.Remarkable feature of the electronic spectrum in the high Tc phase is the appearance of small pockets at the Fermi level. Their presence leads to a two-gap spectrum, which can, in principle, be observed, with the future use of tunneling spectroscopy. This feature leads to non-monotonic and strongly asymmetric pressure dependence of Tc. Other hydrides can be expected to display even higher values of Tc, up to room temperature. The fundamental challenge lays in creation a structure capable of displaying high Tc at ambient pressure.

67 pages,7 figures

References in corpus (15)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Superconductive "sodalite"-like clathrate calcium hydride at high pressures
• Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
• Interplay of electron-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+d
• What superconducts in sulfur hydrides under pressure, and why
• Cubic H${}_3$S around 200 GPa: an atomic hydrogen superconductor stabilized by sulfur
• First-principles study of the pressure and crystal-structure dependences of the superconducting transition temperature in compressed sulfur hydrides
• Definitive experimental evidence for two-band superconductivity in MgB2
• Electron-lattice interaction and its impact on high Tc superconductivity
• Conventional superconductivity at 190 K at high pressures
• Non-BCS thermodynamic properties of H2S superconductor
• The role of striction at magnetic and structural transitions in iron-pnictides
• Superconductivity above 120 kelvin in a chain link molecule
• Superconductivity in palladium hydride and deuteride at 52-61 kelvin
• Phase diagram of the sulfur hydride: transition into high Tc state

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