Progress in high-temperature conventional superconductivity*

Room-temperature superconductivity is becoming realistic given progress in conventional superconductivity: the critical temperature T_c =203 K has been discovered in H₃S under high pressures ~150 GPa[1]. Even higher, nearly room temperature superconductivity has been recently found in superhydride LaH₁₀[2, 3] with T_c ~ 250 K, following the theoretical predictions[4-6]. In this hydride, lanthanum atom is located at the center of the cage of hydrogen H₂₄ and acts as electron donor contributing to electron pairing, while the hydrogen atoms form weak covalent bonds with each other within the cage. This structure is different from that of H₃S, in which each hydrogen atom is connected by a strong covalent bond to the two nearby sulfur atoms.
We will discuss prospects for further increase of T_c to room temperature, which naturally is expecting for hydrides at high pressures. We will present recent studies on YHx, CaHx and other compounds that are considered as potential room-temperature superconductivitors. We will consider various directions to explore high-temperature conventional superconductivity at low and ambient pressures.


1. Drozdov, A.P., et al., Conventional superconductivity at 203 K at high pressures. Nature 2015. 525: p. 73.
2. Drozdov, A.P., et al., Superconductivity at 250 K in lanthanum hydride under high pressures Nature, 2019.
3. Somayazulu, M., et al., Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures. Phys. Rev. Lett., 2019. 122 p. 027001.
4. Peng, F., et al., Hydrogen Clathrate Structures in Rare Earth Hydrides at High Pressures: Possible Route to Room-Temperature Superconductivity. Phys. Rev. Lett., 2017. 119 p. 107001.
5. Liu, H., et al., Potential high-Tc superconducting lanthanum and yttrium hydrides at high pressure. PNAS, 2017. 114: p. 6990.
6. Liu, H., et al., Dynamics and superconductivity in compressed lanthanum superhydride. Phys. Rev. B 2018. 98: p. 100102(R).