Cyclotron Masses in Semiconducting Bi_1−xSb_x Alloys

Abstract

Cyclotron resonance measurements are carried out on a great number of semiconductive BiI-.Sb, alloys in the range of 0.07 < z 2 0.17. The measuring frequencies are 35 and 70 GHz, and the measurements are carried out at helium temperatures. For the smallest cyclotron mass, a linear relationship to the antimony concentration is found. The more rapid increase of the great cyclotron masses and the associated increase of the elongation of the iso-energy surfaces with increasing antimony concentration presents the greatest difficulty as compared to the known dispersion relations of the electron bands.An einer groBen Anzahl von halbleitenden B1 -.Sb,-Legierungen im Bereich 0,07 < < z 5 0,17 werden Zyklotronresonanzmessungen bei MeDfrcquenzen von 35 und 70 GHz und Heliumtemperaturen durchgefuhrt. Fur die kleinste Zyklotronniasse wird em h e a r e r Zusammenhang mit der Antimonkonzentration gefunden. Das starkere Anwachsen der grol3en Zyldotronmassen und die damit verbundene Zunahme der Streckung der Isoenergieflachen mit der Antimonkonzentration stellt die grd3te Schwierigkelt beim Vergleich mit den bekannten Modellvorstellungen dar.

Composition Dependence of the Anisotropy of the Cyclotron Masses in n‐Type Semiconducting Bi1‐xSbx

“…Corresponding to the values of the small band-edge cyclotron mass r n $ O (~) [6] and the literature data for the energy gap 141, simultaneous the relation is satisfied (see equation ( As compared with this, the increase in the anisotropy of the cyclotron masses with rising energy gap, which is found in the range 0.10 x s 0.15, represents a peculiarity. This peculiarity and likewise the behaviour of y in the vicinity of the critical pressure p,.…”

“…(The calculations in [lo] were carried out for the quasi-classical magnetic field range and an ellipsoidal model for the dispersion relation of the electrons.) I n this case, t o obtain (6) it is necessary that the contributions to the wave vector k which are connected with the dielectric constant of the lat- This redistribution is a consequence (i) of the increase in the state density of the energy levels and (ii) of the simultaneous shifting of the levels in the magnetic field (cf., for example, ["I). Corresponding to the cyclotron masses and spin splitting parameters for B parallel to the axes 2' and 3', the first leads first of all to a decrease of A with rising magnetic field after the quasi-ellipsoid a has reached the ultraquantum state (only one occupied level).…”

Concentration anomalies of properties in Bi–Sb semimetallic solid solutions

“…At the L-point of the Brilluoin zone, there is another valence band, separated from the conduction band by a small gap e g E13.6 meV at 0 K [6,7]. The results of studies on the Bi-Sb solid solutions energy spectrum (see, e.g., [6][7][8][9][10][11][12][13]) showed that with increasing Sb content, the T-band moves down in energy, and the direct gap e g , separating the bottom of the conduction band and the top of the valence band in the L-point of the Brilluoin zone (terms L a and L s , respectively), rapidly decreases and at a certain concentration x 1 (x 1 ffi2. 3 various authors) becomes zero and a gapless state is realized.…”

Anomalous Proximity Effect in the Nb-BiSb-Nb Junctions

“…1). To the best of our knowledge, superconducting BiSb-based junctions have not yet been used; we fabricated such junctions not long ago [9], although the unique electron properties of this material have long been known [10]. One of these properties is an abnormally low effective mass of electrons m ‫ء‬ equal to 0.9 3 10 23 m 0 where m 0 is the mass of a free electron and, hence, a very great de Broglie wavelength l ഠ 800 nm in single crystals with 6 at.…”