Interfaces: Hetero- and CollegialA Tribute to Herb Kroemer

Evelyn L. HuHarvard School of Engineering & Applied Sciences

Circa 1980’s . . . ‘come join UCSB’

Jim Merz

‘ We have Herb Kroemer!’

Hetero-interfaces: powerful concept, unifying theme

INTERFACES (at ‘home’)• Hetero-interfaces

− scientifically rich− broad applications

• Collegial interfaces– collaborative environment– broadened impact

Herb:• generated the fundamental ideas• delineated the band structure• brought in MBE to give form to idea

Opportunities at Interfaces

Bandgaps and offsets

6.1 angstrom materials

‘Quantized Conductance’

Quantized Conductance in InAs wires:The exceptional mobility of electrons, and the smooth interfaces ofInAs ‘wires’

with Steve Koester,Colombo Bolognesi,Mason Thomas(~ 1992)

at the interfaces of the ‘6.1’ materials

Transport between superconductors and semiconductors

Exceptional Conductance at low T, zero voltage:Andreev Reflections

with Chanh Nguyen,Mason Thomas(~ 1992)

A healthy skepticism, critical judgment, with an openess to new ideas

The vision to embrace‘blue sky’ and follow it toapplications.

Sharing ideas to promote new collaborations

Interfaces Produce Opportunities

Center for Quantized Electronic Structures

1989 - 2000

Interfaces that generate ideas, guidance, collaborations

Where is the Fermi level?

Type I? Type II?

The interface is key !

Innovator, standard bearer, teacher, mentor, collaborator…Thank you, Herb!