Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improving the performance of Ge$_2$Sb$_2$Te$_5$ materials via nickel
  doping: Towards RF-compatible phase-change devices   High-speed electrical switching of Ge2Sb2Te5 (GST) remains a challenging task
due to the large impedance mismatch between the low-conductivity amorphous
state and the high-conductivity crystalline state. In this letter, we
demonstrate an effective doping scheme using nickel to reduce the resistivity
contrast between the amorphous and crystalline states by nearly three orders of
magnitude. Most importantly, our results show that doping produces the desired
electrical performance without adversely affecting the film's optical
properties. The nickel doping level is approximately 2% and the lattice
structure remains nearly unchanged when compared with undoped-GST. The
refractive indices at amorphous and crystalline states were obtained using
ellipsometry which echoes the results from XRD. The material's thermal
transport properties are measured using time-domain thermoreflectance (TDTR),
showing no change upon doping. The advantages of this doping system will open
up new opportunities for designing electrically reconfigurable high speed
optical elements in the near-infrared spectrum.

33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg