Universal Fermi velocity in highly compressed hydride superconductors

Evgeny F. Talantsev

doi:10.1063/5.0091446

Journals >Matter and Radiation at Extremes >Volume 7 >Issue 5 >Page 058403 > Article

Matter and Radiation at Extremes
Vol. 7, Issue 5, 058403 (2022)

Universal Fermi velocity in highly compressed hydride superconductors

Evgeny F. Talantsev^a)

Author Affiliations

M. N. Miheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, 18, S. Kovalevskoy St., Ekaterinburg 620108, Russia and NANOTECH Centre, Ural Federal University, 19 Mira St., Ekaterinburg 620002, Russia

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DOI: 10.1063/5.0091446 Cite this Article

Evgeny F. Talantsev. Universal Fermi velocity in highly compressed hydride superconductors[J]. Matter and Radiation at Extremes, 2022, 7(5): 058403 Copy Citation Text

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Universal nodal Fermi velocity vF,univ=2.7±0.5×105 m/s for cuprate superconductors. These are the raw data reported by Zhou et al.37 for (La2−xSrx)CuO4 (LSCO), (La2−x−yNdySrx)CuO4 (Nd-LSCO), Bi2Sr2CaCu2O8 (Bi-2212), Bi2Sr2CuO6 (Bi-2201), (Ca2−xNax)CuO2Cl2 (Na-CCOC), and Tl2Ba2CuO6 (Tl-2201).

Fig. 1. Universal nodal Fermi velocity vF,univ=2.7±0.5×105 m/s for cuprate superconductors. These are the raw data reported by Zhou et al.³⁷ for (La_2−xSr_x)CuO₄ (LSCO), (La_2−x−yNd_ySr_x)CuO₄ (Nd-LSCO), Bi₂Sr₂CaCu₂O₈ (Bi-2212), Bi₂Sr₂CuO₆ (Bi-2201), (Ca_2−xNa_x)CuO₂Cl₂ (Na-CCOC), and Tl₂Ba₂CuO₆ (Tl-2201).

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Upper critical field data Bc2(T) and data fit to Eqs. (13) and (14) for unannealed highly compressed sulfur hydride (P = 190 GPa). The raw R(T, Bappl) dataset was that reported by Drozdov et al.1 The deduced values of ξ0, Δ0, Tc, and ΔC/γTc are shown on the figure. The 95% confidence bands are shown by the pink shaded area. The fit quality is R = 0.9985.

Fig. 2. Upper critical field data B_c2(T) and data fit to Eqs. (13) and (14) for unannealed highly compressed sulfur hydride (P = 190 GPa). The raw R(T, B_appl) dataset was that reported by Drozdov et al.¹ The deduced values of ξ0, Δ0, T_c, and ΔC/γT_c are shown on the figure. The 95% confidence bands are shown by the pink shaded area. The fit quality is R = 0.9985.

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Fig. 3. Total B_c2(0) vs T_c dataset for hydrogen-rich superconductors deduced in this work (Table I) and data fits to (a) Eq. (7) and (b) Eq. (5). (a) Free-fitting β = 2.07 ± 0.14 and f=1.19±0.90×10−10 s²/m²; the fit quality is R = 0.9361. (b) β = 2.0 (fixed) and free-fitting f=1.68±0.08×10−10 s²/m²; the fit quality is R = 0.9354.

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Phase and data source	Figures	Pressure (GPa)	T_c (K)	ΔT_c (K)	B_c2(0) (T)	ΔB_c2(0) (T)
Unannealed sulfur hydride [Fig. 3(a) in Ref. 1]	2	155	13.9	0.3	6.3	0.4
Annealed H₃S (Fig. 3 in Ref. 31)	S1(a)	155	185	2	98.8	1.2
Annealed H₃S (Figs. S1 and S2 in Ref. 31)	S1(b)	155	196.1	0.6	71.1	1.1
Annealed H₃S (Fig. 3 in Ref. 31)	S1(c)	160	143.9	1.4	59.2	2.3
Annealed CeH₉ [Fig. S7(a) in Ref. 12], cooling	S2(a)	88	38.8	0.4	16.5	1
Annealed CeH₉ [Fig. 1(c) in Ref. 12], warming	S2(b)	139	88.6	0.3	22.2	0.7
Annealed CeH₉ [Fig. 1(d) in Ref. 12], cooling	S2(c)	137	81.9	0.7	18.4	0.7
Annealed CeH₉ [Fig. 1(d) in Ref. 12], warming	S2(d)	137	82.7	0.7	18.7	0.6
Annealed LaH₁₀ [Fig. 3(a) in Ref. 60]	S3(a)	120	174.8	0.8	90	3
Annealed LaH₁₀ [Fig. 3(b) in Ref. 60]	S3(b)	136	206.2	0.8	136	3
Annealed YD₆ [Fig. S13(a) in Ref. 4]	S4(a)	172	157.7	0.2	124.9	2.4
Annealed YH₆ [Fig. S16(c) in Ref. 4]	S4(b)	200	206.2	0.2	97.2	1.4
Annealed (La,Y)H₁₀ [Fig. S27(b) in Ref. 8]	S5(a)	183	203.5	0.2	101.6	1.8
Annealed (La,Y)H₁₀ [Fig. S28(a) in Ref. 8]	S5(b)	182	234	0.1	135.8	1.5
Annealed (La,Y)H₁₀ [Fig. S28(a) in Ref. 8]	S5(c)	186	234.5	0.1	134	1
Annealed SnH₁₂ [Fig. 4(a) in Ref. 11], cooling	S6(a)	190	62.8	0.4	9	0.2
Annealed SnH₁₂ [Fig. 4(a) in Ref. 11], warming	S6(b)	190	64.1	0.5	8.9	0.2
Annealed ThH₉ [Fig. 4(a) in Ref. 16]	S7(a)	170	151.2	1.5	32	0.9
Annealed ThH₁₀ [Fig. 4(a) in Ref. 16]	S7(b)	170	150.6	0.4	43.4	0.6
Th₄H₁₅ (Ref. 74)		Ambient	8.2	0.15	2.75	0.25