Dirac fermion heating, current scaling, and direct insulator-quantum Hall transition in multilayer epitaxial graphene

Table 1 Sample parameters

	Sample 1	Sample 2	Sample 3	Sample 4
ρ (Ω)	583	520	443	367
n (10¹³ cm⁻²)	2.08	1.98	2.16	2.44
μ (cm²/V.S)	511	605	651	694
B_c (T)	9.2	4.2	6.0	5.7
v _c	94	194	148	178
ρ_xx/ρ_xy at B_c	2.1	3.7	2.5	2.8
μB _c	0.47	0.25	0.39	0.40

Samples 1 and 2 were from the same chip, processed at 1,850°C for 45 min; the former is close to the edge, and the later is near the center. Samples 3 and 4 were also from the same chip, processed at 1,950°C for 30 min; the former is close to the center, and the latter is near the edge. Lower resistivity near the edge is expected in the FTG process; near the center the graphene growth is suppressed because of the higher concentration of Si vapor.