Wydarzenia

Seminarium Międzynarodowego Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur PAN

Fractional Quantum Hall Effect first observation in a 2DHG of selectively doped strained sGe/SiGe/(001)Si-based heterostructures

Oleg A. Mironov^1,2, and David R. Leadley¹

1. Department of Physics, University of Warwick, Coventry, UK; 2. International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw, Poland

The extremely high 2DHG low temperature mobility of over 1.3*106 cm2/Vs (Ps=2.9*1011 cm-2) [1-4] and very low hole effective mass (0.060 ± 0.001)mo determined from Shubnikov-de Haas oscillations has enabled the fractional quantum Hall effect (FQHE) to be observed for the first time in the ranges of magnetic fields up to 35T and temperatures 25mK<T<4.2K. Two Dimensional Holes (2DHG) located in a compressively strained (0.65%) sGe-QW of 20 nm thickness and 100% purity without any Si contamination from Si0.2Ge0.8 barriers. The sGe-QW was selectively doped by boron (single-sided doping with 26 nm spacer between QW and B-layer). The SiGe/(001)Si-based heterostructures were grown by RP-CVD method (ASM, Epsilon 2000) [1-2]. The 2DHG low temperature mobility in our system is more than order of magnitude bigger than previously reported for similar SiGe-based heterostructures, in absence of parallel conduction to the 2DHG channel, and grown by use of LEPE-CVD [3] and MBE [5, 6]. These results confirm that the FQHE is a truly universal and material independent phenomenon, which could be observed in a strained or unstrained heterostructures with 2DEG or 2DHG.

[1] DOBBIE, A., et al., 2012. APL 101, 172108.
[2] MIRONOV O.A. et al., 2014. Thin Solid Films, 557, 329–333.
[3] HASSAN A.H.A., MIRONOV O.A. et al., 2014. APL 104, 132108.
[4] MIRONOV O.A., et al., 2014. Phys. Status Solidi C 11, No. 1, 61–64.
[5] ROSSNER, B.,ISELLA, G.. Isella and VON KANEL, H., 2003. APL 82,754.
[6] IRISAWA,T, MYRONOV M.,MIRONOV,O.A. et al, 2003. APL 82,1425 (2003).