Details
| Original language | English |
|---|---|
| Article number | 045403 |
| Journal | Physical Review B |
| Volume | 97 |
| Issue number | 4 |
| Early online date | 3 Jan 2018 |
| Publication status | Published - 15 Jan 2018 |
Abstract
Epitaxial Bi(111) films were subject to many and partly even controversial studies on the semimetal-semiconductor transition triggered by a robust quantum confinement. The residual conductance was ascribed to conducting surface channels. We investigated ultrathin crystalline Bi films on Si(111) as a function of film thickness d between 20 and 100 bilayers by means of electric transport measurements. Varying temperature and magnetic field, we disentangled two transport channels. One remains indeed metallic at all thicknesses investigated and exhibits a slightly increasing conductance as a function of d, whereas the second is activated with a d-1 dependence of the activation energy, indicating a quasiharmonic confining potential. Both channels reflect the electronic properties of the entire film and do not allow us to strictly separate surface and bulk states. While there is clearly no bulk conductivity, the activated channel is consistently described as electronic excitation into the partly occupied quantum well states, which are also responsible for the metallic conductance and preferentially located close to both interfaces of the film.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Physical Review B, Vol. 97, No. 4, 045403, 15.01.2018.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Controlling conductivity by quantum well states in ultrathin Bi(111) films
AU - Kröger, Philipp
AU - Abdelbarey, D.
AU - Siemens, Marianna
AU - Lükermann, Daniel
AU - Sologub, S.
AU - Pfnür, Herbert
AU - Tegenkamp, Christoph
N1 - ©2018 American Physical Society
PY - 2018/1/15
Y1 - 2018/1/15
N2 - Epitaxial Bi(111) films were subject to many and partly even controversial studies on the semimetal-semiconductor transition triggered by a robust quantum confinement. The residual conductance was ascribed to conducting surface channels. We investigated ultrathin crystalline Bi films on Si(111) as a function of film thickness d between 20 and 100 bilayers by means of electric transport measurements. Varying temperature and magnetic field, we disentangled two transport channels. One remains indeed metallic at all thicknesses investigated and exhibits a slightly increasing conductance as a function of d, whereas the second is activated with a d-1 dependence of the activation energy, indicating a quasiharmonic confining potential. Both channels reflect the electronic properties of the entire film and do not allow us to strictly separate surface and bulk states. While there is clearly no bulk conductivity, the activated channel is consistently described as electronic excitation into the partly occupied quantum well states, which are also responsible for the metallic conductance and preferentially located close to both interfaces of the film.
AB - Epitaxial Bi(111) films were subject to many and partly even controversial studies on the semimetal-semiconductor transition triggered by a robust quantum confinement. The residual conductance was ascribed to conducting surface channels. We investigated ultrathin crystalline Bi films on Si(111) as a function of film thickness d between 20 and 100 bilayers by means of electric transport measurements. Varying temperature and magnetic field, we disentangled two transport channels. One remains indeed metallic at all thicknesses investigated and exhibits a slightly increasing conductance as a function of d, whereas the second is activated with a d-1 dependence of the activation energy, indicating a quasiharmonic confining potential. Both channels reflect the electronic properties of the entire film and do not allow us to strictly separate surface and bulk states. While there is clearly no bulk conductivity, the activated channel is consistently described as electronic excitation into the partly occupied quantum well states, which are also responsible for the metallic conductance and preferentially located close to both interfaces of the film.
UR - http://www.scopus.com/inward/record.url?scp=85040347512&partnerID=8YFLogxK
U2 - 10.1103/physrevb.97.045403
DO - 10.1103/physrevb.97.045403
M3 - Article
AN - SCOPUS:85040347512
VL - 97
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 4
M1 - 045403
ER -