Letter/Comment on: Improved predictions for superconductors
LLetter/Comment on: Improved predictions for superconductors
Dale R. Harshman and Anthony T. Fiory Department of Physics, The College of William and Mary, Williamsburg, VA 23187, USA Bell Labs Retired, Summit, NJ 07901, USA
Abstract
Letter/comment on M. Rini, Physics , s94 (July 27, 2020) and A. Sanna et al ., Phys. Rev. Lett. , 057001 (2020). With novel materials closing in on superconductivity at room temperature, our interest is, indeed, sparked by the Physics Synopsis by Matteo Rini [1], recounting improved superconducting density-functional theory (SCDFT) reported in [2] and noting the <20% accuracy. Predictions of the superconducting transition temperature T C for H S (at 165 K for denoted “SH ”) in [2] and for LaH included in [2] via citation [3] become especially prescient, given the record high T C values measured for compressed hydrides. While somewhat improved, predictions based on SCDFT persistently underestimate the actual T C of LaH , as shown in Fig. 1, which compares pressure dependences of experimental data and theoretical predictions. The black symbols are experimental data (circles from [4], triangles from [5]). As can be seen, predictions from improved SCDFT [3], shown by green square symbols, systematically underestimate experiment, falling 6–14% below data in [4] and 12–17% below data in [5]. Filled red squares ( T C0 ) show predictions from electronic mediation at pressures of experimentally maximal T C in LaH [6], falling within 1% of experiment, similar to the accuracy for 200-K phase H S [6, 7]. Clearly, improvement in current phonon theory [3] for LaH , ascribed as preliminary in [2], takes on greater urgency. Once accomplished, it will likely prompt a reevaluation of the theoretical and experimental landscape for superconductivity near room temperature. References M. Rini, Physics , s94 (July 27, 2020). 2. A. Sanna, E. Pellegrini, and E. K. U. Gross, Phys. Rev. Lett. , 057001 (2020). 3.
I. Errea, F. Belli, L. Monacelli, A. Sanna, T. Koretsune, T. Tadano, R. Bianco, M. Calandra, R. Arita, F. Mauri, and J. A. Flores-Livas, Nature , 66 (2020). 4.
A. P. Drozdov, P. P. Kong, V. S. Minkov, S. P. Besedin, M. A. Kuzovnikov, S. Mozaffari, L. Balicas, F. F. Balakirev, D. E. Graf, V. B. Prakapenka, E. Greenberg, D. A. Knyazev, M. Tkacz, and M. I. Eremets, Nature , 528 (2019). 5.
M. Somayazulu, M. Ahart, A. K. Mishra, Z. M. Geballe, M. Baldini, Y. Meng, V. V. Struzhkin, and R. J. Hemley, Phys. Rev. Lett. , 027001 (2019). 6.
D. R. Harshman and A. T. Fiory, J. Supercond. Nov. Magn. , 2945 (2020). D. R. Harshman and A. T. Fiory, J. Physics: Condens. Matter , 445702 (2017). Fig. 1. Experimental and theoretical superconduct-ing critical temperature T C vs . pressure P for LaH10