Normal vibrations in gallium arsenide

Normal vibrations in gallium arsenide

Solid State C~unications t h e United States. ABSTRACTS Vol. i, pp. 155-202, 1963. Pergamon Press, Inc. Printed in AND TITLES OF P A P E R S CONF...

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Solid State C~unications t h e United States.

ABSTRACTS

Vol. i, pp. 155-202, 1963. Pergamon Press, Inc. Printed in

AND TITLES

OF P A P E R S

CONFERENCE Copenhagen,

PRESENTED

ON L A T T I C E

Denmark,

AT THE

INTERNATIONAL

DYNAMICS

5-9 A u g U s t ,

1963.

The P r o c e e d i n g s o f this C o n f e r e n c e (with the e x c e p t i o n those papers indicated for publication elsewhere) will a p p e a r i n e a r l y 1 9 6 4 as a v o l u m e of the J O U R N A L OF T H E P H Y S I C S A N D C H E M I S T R Y OF S O L I D S .

Session AI.

of

A

A STUDY

OF T H E

CRYSTAL

DYNAMICS

OF ZINC I

G. B o r g o n o v i , G. C a g l i o t i , a n d J.J. A n t a l 2 ( C o m i t a t o N a z i o n a l e l ' E n e r g i a N u c l e a t e C.C.R. E u r a t o m , I s p r a (Varese), I t a l y ) .

A2.

NORMAL

VIBRATIONS

IN G A L L I U M

per

ARSENIDE

G. D o l l i n g a n d J.L.T. W a u g h 3 ( C h a l k R i v e r N u c l e a r L a b o r a t o r i e s , A t o m i c E n e r g y of C a n a d a L i m i t e d , C h a l k River, Ontario, C a n a d a ) The

triple

to o b s e r v e pure

axis

coherent

gallium

arsenide

vibration

propagating

have

determined

been

limited

number

Considerable neutron very

vector,

of r e s u l t s

several

different

have

to the

EO~J

been

studied

in o b t a i n i n g

at 296°K.

various

to the

Physics

modes A

and 184°K.

modes

from

from

Chemistry

Dept.,

University

~onditions (units

Review.

155

of H a w a i i ,

for

a com-

2. V i s i t i n g S c i e n t i s t f r o m U.S® A r m y M a t e r i a l s R e s e a r c h Agency, W a t e r t o w n , Mass.p u n d e r a S e c r e t a r y of the Army's R e s e a r c h and Study Fellowship. 3. On leave

of

resolved

optic

frequencies

of

directions

at 9 5 ° K

However,

been used

crystal

2.5~.

well

experimental

space,

has

crystal

I ~ and

two n o n - d e g e n e r a t e

in r e c i p r o c a l

for p u b l i c a t i o n

' and

River

a single of n o r m a l

of b e t w e e n

also

particularly under

from

frequencies

experienced

obtained points

The

-~00~' E ~ J _

modes was

at C h a l k

scattering

a precision

corresponding

parison

i. S u b m i t t e d

in the with

of n o r m a l

wave

spectrometer

at 296°K°

difficulty

peaks

small

crystal

slow neutron

Honolulu.

at 1012cps)

156

for

LATTICE

these

L 8.55 ~

modes 0.2.

frequencies

CONFERENCE

(at 296°K) Other

are

(a)

have

specific (i,0,0),

T A 1.86 Z 0.02,

L0 7 . 1 5 Z 0.07,

3.42

+ 0.06

lower

than

terms been

and

of v a r i o u s

LATTICE

DYNAMICS

with

These

of

small,

(c)

about from

(0,0.65,0.65): 5.58 ~ 0.08,

generally

slightly An analysis

approximation

analysis

derived

0.08 and

T O 7 . 8 4 Z 0.12,

germanium.

the d i p o l e

6

measured

acoustic

are

for

1 No.

T A 2.36 ~ 0.015,

O.ll,

results

of this

has b e e n

their

0.i0;

6.57 ~

Vol.

T 8.02 ~

(0.5,0~5,0.5):

LA 6.26 Z

to be v e r y

function

modes,

frequencies

A feature

atom appears

assigned:

(b)

and

modifications

out.

distribution

A3.

+ 0.04.

the c o r r e s p o n d i n g

carried

gallium

7.54 Z 0.12

2.36

AND TITLES

T O 7 . 5 6 ~ 0.08,

LA 6 . 8 0 Z 0.06;

8 . 0 8 ~ 0.13,

been

normal

L O 7 . 2 2 Z 0.15,

optic

ABSTRACTS

is that +0.04

one

the

e.

model

has

charge

The

in

on the

frequency

of the f o r c e

models.

OF Z I N C

E. M a l i s z e w s k i , J. R o s o l o w s k i , 4 D. S l e d z l e w s k a a n d A. C z a c h o r ( L a b o r a t o r y II for N u c l e a r P h y s i c s , I n s t i t u t e of N u c l e a r R e s e a r c h , Swierk, Poland) Phonon in the

dispersion

symmetry

spectrometer expressions Karman

initial the

branches

for

relations

third

do n o t

fit

A possible

A4.

DYNAMICS

4. G u e s t

[000 9

direction the

of the

shows

the

triple

usin~

force

optical

curves

crystal

the B o r n - y o n

and

in shape

of

experimenand

branches

fit

and acoustical

the p o l a r i z a t i o n

of this

axis

interactions

theoretical fit

measured

Theoretical

the l o n g i t u d i n a l

The

theoretical

were

methods.

a good

~I~0~

with

explanation

wither

normal

to the

in shape

discrepancy

or in

is given.

OF N I O B I U M

on l e a v e

5. N a t i o n a l R e s e a r c h Tokyo, Japan.

using

calQula~ed

curves.

Woods (Chalk River Limited)

is a t r a n s i t i o n

Scientist

were

Comparison

Y. N a k a g a w a 5 a n d A . D . B . A t o m i c E n e r g y of C a n a d a Niobium

[01103

crystals

time-of-flight

the d i r e c t i o n

~i~03

single

fourth neighbour

calculated

magnitude.

LATTICE

and

type.

For

of the

in the

plane

[0001~,

the d i r e c t i o n

slopes.

shapes

basal

these

and g e n e r a l

curves

in zinc

the c o l d n e u t r o n

theory with

central tal

directions

and for

relations

Council

metal

with

a high

from Brookhaven of C a n a d a

Nuclear

superconducting

National

Fellow

Laboratories,

Laboratory,

from Gakushium

U.S.A.

University,