Valence band energy spectrum of HgTe quantum wells with an inverted band structure / Minkov G. M.,Aleshkin V. Ya.,Rut O. E.,Sherstobitov A. A.,Germanenko A. V.,Dvoretski S. A.,Mikhailov N. N. // PHYSICAL REVIEW B. - 2017. - V. 96, l. 3.

ISSN/EISSN:

2469-9950 / 2469-9969

Type:

Article

Abstract:

The energy spectrum of the valence band in HgTe/Cd-x Hg1-x Te quantum wells of a width (8-20) nm has been studied experimentally by magnetotransport effects and theoretically in the framework of a four-band kP method. Comparison of the Hall density with the density found from a period of the Shubnikov-de Haas (SdH) oscillations clearly shows that the degeneracy of states of the top of the valence band is equal to 2 at the hole density p < 5.5 x 10(11) cm(-2). Such degeneracy does not agree with the calculations of the spectrum performed within the framework of the four-band kP method for symmetric quantum wells. These calculations show that the top of the valence band consists of four spin-degenerate extremes located at k not equal 0 (valleys) which gives the total degeneracy K = 8. It is shown that taking into account the ``mixing of states{''} at the interfaces leads to the removal of the spin degeneracy that reduces the degeneracy to K = 4. Accounting for any additional asymmetry, for example, due to the difference in the mixing parameters at the interfaces, the different broadening of the boundaries of the well, etc., leads to reduction of the valleys degeneracy, making K = 2. It is noteworthy that for our case twofold degeneracy occurs due to degeneracy of two single-spin valleys. The hole effective mass (m(h)) determined from analysis of the temperature dependence of the amplitude of the SdH oscillations shows that mh is equal to (0.25 +/- 0.02) m(0) and weakly increases with the hole density. Such a value of m(h) and its dependence on the hole density are in a good agreement with the calculated effective mass.

Author keywords:

CYCLOTRON-RESONANCE

DOI:

10.1103/PhysRevB.96.035310

Web of Science ID:

ISI:000406291200002

Соавторы в МНС:

Другие поля

Поле	Значение
Month	JUL 26
Publisher	AMER PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	035310
EISSN	2469-9969
Keywords-Plus	CYCLOTRON-RESONANCE
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
Funding-Acknowledgement	Russian Foundation for Basic Research {[}16-02-00516, 15-51-06001, 15-02-02072]; Act 211 Government of the Russian Federation {[}02. A03.21.0006]; Ministry of Education and Science of the Russian Federation {[}3.9534.2017/BP]
Funding-Text	We are grateful to E.L. Ivchenko and M. Nestoklon for useful discussions. The work has been supported in part by the Russian Foundation for Basic Research (Grants No. 16-02-00516, No. 15-51-06001, and No. 15-02-02072), by Act 211 Government of the Russian Federation, Agreement No. 02. A03.21.0006, and by the Ministry of Education and Science of the Russian Federation under Project No. 3.9534.2017/BP.
Number-of-Cited-References	27
Usage-Count-Last-180-days	3
Usage-Count-Since-2013	3
Journal-ISO	Phys. Rev. B
Doc-Delivery-Number	FB6ZP