Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO3

P. D. C. King; R. H. He; T. Eknapakul; P. Buaphet; S-K Mo; Y. Kaneko; S. Harashima; Y. Hikita; M. S. Bahramy; C. Bell; Z. Hussain; Y. Tokura; Z-X Shen; H. Y. Hwang; F. Baumberger; W. Meevasana

doi:10.1103/PhysRevLett.108.117602

Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO₃

P. D. C. King, R. H. He, T. Eknapakul, P. Buaphet, S-K Mo, Y. Kaneko, S. Harashima, Y. Hikita, M. S. Bahramy, C. Bell, Z. Hussain, Y. Tokura, Z-X Shen, H. Y. Hwang, F. Baumberger, W. Meevasana

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Abstract

We demonstrate the formation of a two-dimensional electron gas (2DEG) at the (100) surface of the 5d transition-metal oxide KTaO3. From angle-resolved photoemission, we find that quantum confinement lifts the orbital degeneracy of the bulk band structure and leads to a 2DEG composed of ladders of subband states of both light and heavy carriers. Despite the strong spin-orbit coupling, our measurements provide a direct upper bound for the potential Rashba spin splitting of only Delta k(parallel to) similar to 0.02 angstrom(-1) at the Fermi level. The polar nature of the KTaO₃(100) surface appears to help mediate the formation of the 2DEG as compared to nonpolar SrTiO₃(100).

Original language	English
Article number	117602
Number of pages	5
Journal	Physical Review Letters
Volume	108
Issue number	11
DOIs	https://doi.org/10.1103/PhysRevLett.108.117602
Publication status	Published - 14 Mar 2012

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10.1103/PhysRevLett.108.117602

king2012physrevlett117602
© 2012 American Physical Society
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Fellowship - Unspent EPSRC Balance: Fellowship - Unspent Funds
King, P. (PI)
EPSRC
1/10/11 → 31/03/12
Project: Fellowship
Topological Protection and NonEquilibriu: Topological Protection and NonEquilibrium States in Strongly Correlated Electron Systems
Wahl, P. (PI), Baumberger, F. (CoI), Davis, S. (CoI), Green, A. (CoI), Hooley, C. (CoI), Keeling, J. (CoI) & Mackenzie, A. (CoI)
EPSRC
1/09/11 → 31/08/17
Project: Standard

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King, P. D. C., He, R. H., Eknapakul, T., Buaphet, P., Mo, S.-K., Kaneko, Y., Harashima, S., Hikita, Y., Bahramy, M. S., Bell, C., Hussain, Z., Tokura, Y., Shen, Z.-X., Hwang, H. Y., Baumberger, F., & Meevasana, W. (2012). Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO₃. Physical Review Letters, 108(11), Article 117602. https://doi.org/10.1103/PhysRevLett.108.117602

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title = "Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO3",

abstract = "We demonstrate the formation of a two-dimensional electron gas (2DEG) at the (100) surface of the 5d transition-metal oxide KTaO3. From angle-resolved photoemission, we find that quantum confinement lifts the orbital degeneracy of the bulk band structure and leads to a 2DEG composed of ladders of subband states of both light and heavy carriers. Despite the strong spin-orbit coupling, our measurements provide a direct upper bound for the potential Rashba spin splitting of only Delta k(parallel to) similar to 0.02 angstrom(-1) at the Fermi level. The polar nature of the KTaO3(100) surface appears to help mediate the formation of the 2DEG as compared to nonpolar SrTiO3(100).",

author = "King, {P. D. C.} and He, {R. H.} and T. Eknapakul and P. Buaphet and S-K Mo and Y. Kaneko and S. Harashima and Y. Hikita and Bahramy, {M. S.} and C. Bell and Z. Hussain and Y. Tokura and Z-X Shen and Hwang, {H. Y.} and F. Baumberger and W. Meevasana",

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doi = "10.1103/PhysRevLett.108.117602",

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King, PDC, He, RH, Eknapakul, T, Buaphet, P, Mo, S-K, Kaneko, Y, Harashima, S, Hikita, Y, Bahramy, MS, Bell, C, Hussain, Z, Tokura, Y, Shen, Z-X, Hwang, HY, Baumberger, F & Meevasana, W 2012, 'Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO₃', Physical Review Letters, vol. 108, no. 11, 117602. https://doi.org/10.1103/PhysRevLett.108.117602

TY - JOUR

T1 - Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO3

AU - King, P. D. C.

AU - He, R. H.

AU - Eknapakul, T.

AU - Buaphet, P.

AU - Mo, S-K

AU - Kaneko, Y.

AU - Harashima, S.

AU - Hikita, Y.

AU - Bahramy, M. S.

AU - Bell, C.

AU - Hussain, Z.

AU - Tokura, Y.

AU - Shen, Z-X

AU - Hwang, H. Y.

AU - Baumberger, F.

AU - Meevasana, W.

PY - 2012/3/14

Y1 - 2012/3/14

N2 - We demonstrate the formation of a two-dimensional electron gas (2DEG) at the (100) surface of the 5d transition-metal oxide KTaO3. From angle-resolved photoemission, we find that quantum confinement lifts the orbital degeneracy of the bulk band structure and leads to a 2DEG composed of ladders of subband states of both light and heavy carriers. Despite the strong spin-orbit coupling, our measurements provide a direct upper bound for the potential Rashba spin splitting of only Delta k(parallel to) similar to 0.02 angstrom(-1) at the Fermi level. The polar nature of the KTaO3(100) surface appears to help mediate the formation of the 2DEG as compared to nonpolar SrTiO3(100).

AB - We demonstrate the formation of a two-dimensional electron gas (2DEG) at the (100) surface of the 5d transition-metal oxide KTaO3. From angle-resolved photoemission, we find that quantum confinement lifts the orbital degeneracy of the bulk band structure and leads to a 2DEG composed of ladders of subband states of both light and heavy carriers. Despite the strong spin-orbit coupling, our measurements provide a direct upper bound for the potential Rashba spin splitting of only Delta k(parallel to) similar to 0.02 angstrom(-1) at the Fermi level. The polar nature of the KTaO3(100) surface appears to help mediate the formation of the 2DEG as compared to nonpolar SrTiO3(100).

U2 - 10.1103/PhysRevLett.108.117602

DO - 10.1103/PhysRevLett.108.117602

M3 - Article

SN - 0031-9007

VL - 108

JO - Physical Review Letters

JF - Physical Review Letters

IS - 11

M1 - 117602

ER -

Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO3

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Fellowship - Unspent EPSRC Balance: Fellowship - Unspent Funds

Topological Protection and NonEquilibriu: Topological Protection and NonEquilibrium States in Strongly Correlated Electron Systems

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Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO₃